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1
Duan, Dewen, Jianhao Yang, Yi Tang, and Yi-Yuan Xie. "Diamond-Based Fiber-Optic Fabry–Perot Interferometer with Ultrawide Refractive-Index Measurement Range." Photonics 11, no. 8 (2024): 763. http://dx.doi.org/10.3390/photonics11080763.
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The majority of Fabry–Perot interferometer (FPI) tip refractive index (RI) sensors utilize silica optical fiber as the cavity material, with an RI of approximately 1.45. This restricts their applicability in measuring the RI of liquids with an RI of approximately 1.45. Here, we propose a fiber-optic FPI-tip RI sensor by bonding a flat, thin diamond film onto the apex of a single-mode optical fiber. The FPI cavity is constructed from a diamond with an RI of approximately 2.4, theoretically enabling the sensor to achieve an ultrawide RI measurement range of 1 to 2.4. A theoretical comparison of its measurement performance was conducted with that of an FPI-tip RI sensor whose cavity is formed by silica fiber. Additionally, an experimental examination of the device’s RI measurement performance was conducted. The results show that the sensor has visibility to the RI unit of −0.4362/RIU in the RI range of 1.33 to 1.40. Combined with other narrow-RI-ranged high-sensitivity sensors, our proposed RI sensor has the potential for use in a wide range of applications.
2
Ahsani, Vahid, Farid Ahmed, Martin Jun, and Colin Bradley. "Tapered Fiber-Optic Mach-Zehnder Interferometer for Ultra-High Sensitivity Measurement of Refractive Index." Sensors 19, no. 7 (2019): 1652. http://dx.doi.org/10.3390/s19071652.
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A Mach-Zehnder interferometer (MZI) based fiberoptic refractive index (RI) sensor is constructed by uniformly tapering standard single mode fiber (SMF) for RI measurement. A custom flame-based tapering machine is used to fabricate microfiber MZI sensors directly from SMFs. The fabricated MZI device does not require any splicing of fibers and shows excellent RI sensitivity. The sensor with a cladding diameter of 35.5 µm and length of 20 mm exhibits RI sensitivity of 415 nm/RIU for RI range of 1.332 to 1.384, 1103 nm/RIU for RI range of 1.384 to 1.4204 and 4234 nm/RIU for RI range of 1.4204 to 1.4408, respectively. The sensor reveals a temperature sensitivity of 0.0097 nm/°C, which is relatively low in comparison to its ultra-high RI sensitivity. The proposed inexpensive and highly sensitive optical fiber RI sensors have numerous applications in chemical and biochemical sensing fields.
3
Mohd Syahnizam Sulaiman, Punithavathi Thirunavakkarasu, Jean-Louis Auguste, Georges Humbert, Farah Sakiinah Roslan, and Norazlina Saidin. "Long Period Fiber Grating for Refractive Index Sensing." Journal of Advanced Research in Applied Sciences and Engineering Technology 30, no. 2 (2023): 154–62. http://dx.doi.org/10.37934/araset.30.2.154162.
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Refractive index (RI) sensors are very valuable in first level detection of changes to the environment. In this project an optical fiber-based sensor is proposed to detect changes in surrounding RI. Most optical fiber sensors require tapering to be done to enhance the light interaction with the surrounding. This causes the fiber to become fragile and difficult to handle. In this research, optical fibers with long period gratings (LPG) are proposed to overcome this issue. Zinc Oxide (ZnO) nanomaterial was deposited over the LPG region using seeding method to enhance the performance of the sensor. The LPG fiber sensor was then used to investigate RI changes in the environment. A broadband laser source was used as the input and an optical spectrum analyser was used to observe the output light spectrum of the LPG sensor for different refractive index mediums. The ZnO coated LPG showed a sensitivity of 428.57 nm/RIU over an RI range of 1 – 1.3578.
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Teng, Deng, Liu, et al. "Refractive Index Sensor Based on Twisted Tapered Plastic Optical Fibers." Photonics 6, no. 2 (2019): 40. http://dx.doi.org/10.3390/photonics6020040.
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We proposed a refractive index (RI) sensor employing two twisted tapered plastic optical fibers (POFs). The tapered POFs were fabricated by a heating and drawing method and were twisted around each other to form a coupled structure. The sensor consisted of two input ports, a twisted region, and two output ports. The tapered POF could make the light couple from one POF to the other easily. The twisted tapered POFs could constitute a self-referencing sensor, and by monitoring the changes of the coupling ratio, the variations of the external medium RIs could be measured. The RI sensing performances for the sensors with different fiber diameters and twisted region lengths were studied. The sensitivities of 1700%/RIU and −3496%/RIU in the RI ranges of 1.37–1.41 and 1.41–1.44 were obtained, respectively. The sensor is a low-cost solution for liquid RI measurement, which has the features of simple structure and easy fabrication.
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Mu, Zonghao, Tian Tian, Yiwei Ma, Song Li, and Tao Geng. "Ultra-Compact Mach–Zehnder Refractometer Based on Rice-Shaped Air Cavity Beam Expansion." Photonics 12, no. 6 (2025): 602. https://doi.org/10.3390/photonics12060602.
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This paper reports and demonstrates, for the first time, a Mach–Zehnder interferometer (MZI) sensor for refractive index (RI) detection based on a rice-shaped air cavity (RAC). In this design, RACs are inserted on both sides of a no-core fiber (NCF), functioning as a beam expander and receiver. When the input light enters the NCF through the RAC, it is fully excited from the fundamental mode to higher-order modes within just 500 μm of propagation. This enables the sensor to achieve exceptionally high sensitivity in external RI detection. By adjusting the width of the RAC, the RI sensitivity can be effectively tuned. When the RAC measures 30.6 × 70 μm, the two selected transmission peaks reach maximum RI sensitivities of 1550.41 nm/RIU and 1810.89 nm/RIU, respectively. Notably, the total length of the sensor is only 0.64 mm, offering a promising approach for the development of ultra-compact RI sensors in the future.
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Takashima, Yuusuke, Masanobu Haraguchi, and Yoshiki Naoi. "GaN-Based High-Contrast Grating for Refractive Index Sensor Operating Blue–Violet Wavelength Region." Sensors 20, no. 16 (2020): 4444. http://dx.doi.org/10.3390/s20164444.
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Owing to its versatility, optical refractive index (RI) sensors with compact size and high chemical stability are very suitable for a wide range of the applications in the internet of things (IoT), such as immunosensor, disease detection, and blood mapping. In this study, a RI sensor with very simple system and high chemical stability was developed using GaN-based high-contrast grating (HCG). The designed HCG pattern was fabricated on GaN-film grown on c-plane sapphire substrate. The fabricated GaN-HCG sensor can detect minuscule RI change of 1.71 × 10–3 with extreme simple surface normal irradiation system. The light behavior inside the GaN-HCG was discussed using numerical electromagnetic field calculation, and the deep understand of the sensing mechanism was provided. The simple system and very high chemical stability of our sensor exploit RI sensing applications in IoT society.
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Leal-Junior, Arnaldo, Guilherme Lopes, Leandro C. Macedo, Welton Duque, Anselmo Frizera, and Carlos Marques. "Heterogeneous Optical Fiber Sensor System for Temperature and Turbidity Assessment in Wide Range." Biosensors 12, no. 11 (2022): 1041. http://dx.doi.org/10.3390/bios12111041.
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This paper presents the development of an optical fiber sensor system for multiparametric assessment of temperature and turbidity in liquid samples. The sensors are based on the combination between fiber Bragg gratings (FBGs), intensity variation and surface plasmon resonance (SPR) sensors. In this case, the intensity variation sensors are capable of detecting turbidity with a resolution of about 0.5 NTU in a limited range between 0.02 NTU and 100 NTU. As the turbidity increases, a saturation trend in the sensor is observed. In contrast, the SPR-based sensor is capable of detecting refractive index (RI) variation. However, RI measurements in the turbidity calibrated samples indicate a significant variation on the RI only when the turbidity is higher than 100 NTU. Thus, the SPR-based sensor is used as a complementary approach for the dynamic range increase of the turbidity assessment, where a linearity and sensitivity of 98.6% and 313.5 nm/RIU, respectively, are obtained. Finally, the FBG sensor is used in the temperature assessment, an assessment which is not only used for water quality assessment, but also in temperature cross-sensitivity mitigation of the SPR sensor. Furthermore, this approach also leads to the possibility of indirect assessment of turbidity through the differences in the heat transfer rates due to the turbidity increase.
8
Wang, Xiangxian, Xiaoxiong Wu, Jiankai Zhu, Zhiyuan Pang, Hua Yang, and Yunping Qi. "Theoretical Investigation of a Highly Sensitive Refractive-Index Sensor Based on TM0 Waveguide Mode Resonance Excited in an Asymmetric Metal-Cladding Dielectric Waveguide Structure." Sensors 19, no. 5 (2019): 1187. http://dx.doi.org/10.3390/s19051187.
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This study proposes a highly sensitive refractive-index (RI) sensor based on a TM0 waveguide mode resonance excited in an asymmetric metal-cladding dielectric waveguide structure, where the analyte serves as the guiding layer. By scanning the wavelength at fixed angles of incidence, the reflection spectra of the sensor were obtained. The results showed that the resonance wavelength redshifted dramatically with increases in the analyte RI, which indicates that this approach can be used to sense both the resonance wavelength and the analyte RI. Based on this approach, we investigated the sensing properties, including the sensitivity and figure of merit, at fixed incident angles of 60° and 45°, at which the sensitivity of the sensor reached 7724.9 nm/RIU (refractive index units) and 1339 nm/RIU, respectively. Compared with surface plasmon resonance sensors, which are based on a similar structure, the proposed sensor can accept a more flexible range of incident angles and a wider sensing range of analyte RI. This approach thus has tremendous potential for use in numerous sensing domains, such as biochemical and medical analyses.
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Fotiadis, Konstantinos, Evangelia Chatzianagnostou, Dimosthenis Spasopoulos, et al. "Theoretical and Experimental Analysis of Single-Arm Bimodal Plasmo-Photonic Refractive Index Sensors." Sensors 24, no. 12 (2024): 3705. http://dx.doi.org/10.3390/s24123705.
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In this paper, we study both theoretically and experimentally the sensitivity of bimodal interferometric sensors where interference occurs between two plasmonic modes with different properties propagating in the same physical waveguide. In contrast to the well-known Mach–Zehnder interferometric (MZI) sensor, we show for the first time that the sensitivity of the bimodal sensor is independent of the sensing area length. This is validated by applying the theory to an integrated plasmo-photonic bimodal sensor that comprises an aluminum (Al) plasmonic stripe waveguide co-integrated between two accessible SU-8 photonic waveguides. A series of such bimodal sensors utilizing plasmonic stripes of different lengths were numerically simulated, demonstrating bulk refractive index (RI) sensitivities around 5700 nm/RIU for all sensor variants, confirming the theoretical results. The theoretical and numerical results were also validated experimentally through chip-level RI sensing experiments on three fabricated SU-8/Al bimodal sensors with plasmonic sensing lengths of 50, 75, and 100 μm. The obtained experimental RI sensitivities were found to be very close and equal to 4464, 4386, and 4362 nm/RIU, respectively, confirming that the sensing length has no effect on the bimodal sensor sensitivity. The above outcome alleviates the design and optical loss constraints, paving the way for more compact and powerful sensors that can achieve high sensitivity values at ultra-short sensing lengths.
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An, Wei, Chao Li, Dong Wang, et al. "Flat Photonic Crystal Fiber Plasmonic Sensor for Simultaneous Measurement of Temperature and Refractive Index with High Sensitivity." Sensors 22, no. 23 (2022): 9028. http://dx.doi.org/10.3390/s22239028.
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A compact temperature-refractive index (RI) flat photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is presented in this paper. Sensing of temperature and RI takes place in the x- and y- polarization, respectively, to avoid the sensing crossover, eliminating the need for matrix calculation. Simultaneous detection of dual parameters can be implemented by monitoring the loss spectrum of core modes in two polarizations. Compared with the reported multi-function sensors, the designed PCF sensor provides higher sensitivities for both RI and temperature detection. A maximum wavelength sensitivity of −5 nm/°C is achieved in the temperature range of −30–40 °C. An excellent optimal wavelength sensitivity of 17,000 nm/RIU is accomplished in the RI range of 1.32–1.41. The best amplitude sensitivity of RI is up to 354.39 RIU−1. The resolution of RI and temperature sensing is 5.88 × 10−6 RIU and 0.02 °C, respectively. The highest value of the figure of merit (FOM) is 216.74 RIU−1. In addition, the flat polishing area of the gold layer reduces the manufacturing difficulty. The proposed sensor has the characteristics of high sensitivity, simple structure, good fabrication repeatability, and flexible operation. It has potential in medical diagnosis, chemical inspection, and many other fields.
11
Li, Lijun, Tianzong Xu, Yinming Liu, et al. "In-Fiber Closed Cavity Interferometric High-Resolution Aqueous Solution and Alcohol Gas Refractometer." Sensors 19, no. 10 (2019): 2319. http://dx.doi.org/10.3390/s19102319.
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An optical fiber interferometric refractometer for alcohol gas concentration and low refractive index (RI) solution (with 1.33–1.38 RI range) measurement is theoretically and experimentally demonstrated. The refractometer is based on a single-mode thin-core single-mode (STS) interferometric structure. By embedding a suitably sized air cavity at the splicing point, high-order cladding modes are successfully excited, which makes the sensor more suitable for low RI solution measurement. The effect of the air cavity’s diameter on the sensitivity of alcohol gas concentration was analyzed experimentally, which proved that RI sensitivity will increase with an enlarged diameter of the air cavity. On this basis, the air cavity is filled with graphene in order to improve the sensitivity of the sensor; and the measured sensitivity of the alcohol gas concentration is −1206.1 pm/%. Finally, the characteristics of the single-cavity structure, graphene-filled structure and double-cavity structure sensors are demonstrated, and the linear RI sensitivities are −54.593 nm/RIU (refractive index unit), −85.561 nm/RIU and 359.77 nm/RIU, respectively. Moreover, these sensor structures have the advantages of being compact and easily prepared.
12
Khanikar, Tulika, and Vinod Kumar Singh. "A D-shaped elliptical hollow core fiber SPR sensor." Journal of Physics: Conference Series 2357, no. 1 (2022): 012004. http://dx.doi.org/10.1088/1742-6596/2357/1/012004.
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A D-shaped elliptical hollow core fiber surface plasmon resonance (SPR) sensor is proposed and analyzed here using gold and titanium oxide (TiO2) layer. The fiber geometry consists of a doped elliptical core with a concentric central elliptical air hole. A finite element method-based simulation software COMSOL Multiphysics is used for numerical analysis. Both gold and TiO2 layers are optimized. The sensor responds over a wide range of refractive index (RI) from 1.33 to 1.40. The average sensitivity obtained for the designed sensor is 4142.85nm/RIU (RI Unit) whereas that for a single mode fiber (SMF) is only 897.55nm/RIU. So, our designed sensor gives more than 4 times enhanced sensitivity and proves to be a potential alternative of SMF based low cost, compatible SPR sensors by covering the low sensitivity issue suffered by SMF sensors.
13
Al-Hmoud, M. "High-Sensitivity and Wide Detection-Range Refractive-Index Sensor Based on Amplitude Change in Slotted Photonic Crystal Nanobeam Cavity." Journal of Nanoelectronics and Optoelectronics 18, no. 6 (2023): 673–79. http://dx.doi.org/10.1166/jno.2023.3435.
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High Q-factor is essential for the realization of high sensitivity photonic crystal-based sensors. The Q-factor is usually optimized for a specific refractive-index (RI) value of the ambient background. However, a small change in the RI reduces the Q value, and therefore limits the performance of the sensor to a narrow RI range. Here, we report a high-sensitivity RI sensor with a wide detection-range based on amplitude change of the fundamental mode in slotted photonic crystal nanobeam cavity. Both wavelength and amplitude sensitivity of 333 nm/RIU and 188/RIU are realized in the RI range from 1.3 to 1.6, respectively. To the best of our knowledge, this represents the widest sensing range ever reported in photonic crystal cavities. Owing to the wide sensing range and the insignificance of the Q value, this approach would find applications in various research areas in integrated lab-on-chip systems for optofluidic- and bio-sensing applications.
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Yanase, Yuhki, Kyohei Yoshizaki, Kaiken Kimura, Tomoko Kawaguchi, Michihiro Hide, and Shigeyasu Uno. "Development of SPR Imaging-Impedance Sensor for Multi-Parametric Living Cell Analysis." Sensors 19, no. 9 (2019): 2067. http://dx.doi.org/10.3390/s19092067.
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Label-free evaluation and monitoring of living cell conditions or functions by means of chemical and/or physical sensors in a real-time manner are increasingly desired in the field of basic research of cells and clinical diagnosis. In order to perform multi-parametric analysis of living cells on a chip, we here developed a surface plasmon resonance (SPR) imaging (SPRI)-impedance sensor that can detect both refractive index (RI) and impedance changes on a sensor chip with comb-shaped electrodes. We then investigated the potential of the sensor for label-free and real-time analysis of living cell reactions in response to stimuli. We cultured rat basophilic leukemia (RBL)-2H3 cells on the sensor chip, which was a glass slide coated with comb-shaped electrodes, and detected activation of RBL-2H3 cells, such as degranulation and morphological changes, in response to a dinitro-phenol-conjugated human serum albumin (DNP-HSA) antigen. Moreover, impedance analysis revealed that the changes of impedance derived from RBL-2H3 cell activation appeared in the range of 1 kHz–1 MHz. Furthermore, we monitored living cell-derived RI and impedance changes simultaneously on a sensor chip using the SPRI-impedance sensor. Thus, we developed a new technique to monitor both impedance and RI derived from living cells by using a comb-shaped electrode sensor chip. This technique may enable us to clarify complex living cell functions which affect the RI and impedance and apply this to medical applications, such as accurate clinical diagnosis of type I allergy.
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Jia, Shuo, Aiwen Ma, Hanpeng Dong, and Shanhong Xia. "Quantifiable Effect of Interparticle Plasmonic Coupling on Sensitivity and Tuning Range for Wavelength-Mode LSPR Fiber Sensor Fabricated by Simple Immobilization Method." Sensors 22, no. 23 (2022): 9075. http://dx.doi.org/10.3390/s22239075.
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Herein a gold nanosphere (AuNS)-coated wavelength-mode localized surface plasmon resonance (LSPR) fiber sensor was fabricated by a simple and time-saving electrostatic self-assembly method using poly(allylamine hydrochloride). Based on the localized enhanced coupling effect between AuNSs, the LSPR spectrums of the AuNS monolayer with good dispersity and high density exhibited a favourable capability for refractive index (RI) measurement. Based on the results obtained from the optimization for AuNS distribution, sensing length, and RI range, the best RI sensitivity of the fiber modified by 100 nm AuNS reached up to about 2975 nm/RIU, with the surrounding RI range from 1.3322 to 1.3664. Using an 80 nm AuNS-modified fiber sensor, the RI sensitivity of 3953 nm/RIU was achieved, with the RI range increased from 1.3744 to 1.3911. The effect of sensing length to RI sensitivity was proven to be negligible. Furthermore, the linear relationship between the RI sensitivity and plasma resonance frequency of the bulk metal, which was dependent on the interparticle plasmon coupling effect, was quantified. Additionally, the resonance peak was tuned from 539.18 nm to 820.48 nm by different sizes of AuNSs-coated fiber sensors at a RI of 1.3322, which means the spectrum was extended from VIS to NIR. It has enormous potential in hypersensitive biochemistry detection at VIS and NIR ranges.
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Meng, Ge, Nannan Luan, Hao He, Fan Lei, and Jianfei Liu. "Side-Opened Hollow Fiber-Based SPR Sensor for High Refractive Index Detection." Sensors 24, no. 13 (2024): 4335. http://dx.doi.org/10.3390/s24134335.
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To facilitate the sensor fabrication and sensing operation in microstructured optical fiber-based surface plasmon resonance (SPR) sensors for high refractive index (RI) detection, we propose a special hollow fiber-based SPR sensor that comprises an opening on its body side and a thin gold layer coated on its outer surface. The analyte is able to flow into the hollow core through the side-opening to form new fiber core, with the Gaussian-like mode propagating in it. We investigate the sensing performance of the proposed sensor in a higher RI range of 1.48 to 1.54 at two feasible schemes: one is to only fill the fiber core with analyte (Scheme A), and the other is to directly immerse the sensor in the analyte (Scheme B). The results demonstrate that our sensor exhibits higher wavelength sensitivity at Scheme A with a maximum wavelength sensitivity of 12,320 nm/RIU, while a greater amplitude sensitivity was found at Scheme B with a maximum amplitude sensitivity of 1146 RIU−1. Our proposed sensor features the advantages of simple fabrication, flexible operation, easy analyte filling and replacing, enhanced real-time detection capabilities, high RI detection, and very high wavelength sensitivity and amplitude sensitivity, which makes it more competitive in SPR sensing applications.
17
Li, Jinke, Shiru Jiang, Stuart Aberdeen, and Sang-Shin Lee. "Highly Efficient Refractive Index Sensor Based on a Dual-Side Polished SMS Fiber Enabled by Femtosecond Laser Writing." Sensors 23, no. 7 (2023): 3651. http://dx.doi.org/10.3390/s23073651.
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Fiber-optic refractive index (RI) sensors based on wavelength-shift-based interrogation continue to present a challenge in achieving high sensitivity for a wide detection range. In this paper, we propose a sensor for determining the RI of liquids based on femtosecond laser (fs-laser) writing of a dual-side polished singlemode–multimode–singlemode (SMS) fiber. The proposed sensor can determine the RI value of a surrounding liquid by detecting the dip wavelength in the transmission spectrum of the light propagating through the sensing area. The high RI sensitivity is attributed to the increased interaction area established by the fs-laser, which creates hydrophilic surfaces and maintains the wide detection range of the SMS structure. The results of the wavelength-shift-based interrogation reveal that the fabricated device exhibited a high sensitivity of 161.40 nm per refractive index unit (RIU) over a wide RI detection range of 0.062 RIU. The proposed device has high processing accuracy and a simple manufacturing process. Hence, it has the potential to be used as a lab-on-fiber sensing platform in chemical and biotechnological applications.
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Han, Haixia, Donglian Hou, Nannan Luan, et al. "Surface Plasmon Resonance Sensor Based on Dual-Side Polished Microstructured Optical Fiber with Dual-Core." Sensors 20, no. 14 (2020): 3911. http://dx.doi.org/10.3390/s20143911.
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A surface plasmon resonance (SPR) sensor based on a dual-side polished microstructured optical fiber (MOF) with a dual core is proposed for a large analyte refractive index (RI; na) detection range. Gold is used as a plasmonic material coated on the polished surface, and analytes can be directly contacted with the gold film. The special structure not only facilitates the fabrication of the sensor, but also can work in the na range of 1.42–1.46 when the background material RI is 1.45, which is beyond the reach of other traditional MOF-SPR sensors. The sensing performance of the sensor was investigated by the wavelength and amplitude interrogation methods. The detailed numerical results showed that the proposed sensor can work effectively in the na range of 1.35–1.47 and exhibits higher sensitivity in the na range of 1.42–1.43.
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Nazeri, Kaveh, Farid Ahmed, Vahid Ahsani, et al. "Hollow-Core Photonic Crystal Fiber Mach–Zehnder Interferometer for Gas Sensing." Sensors 20, no. 10 (2020): 2807. http://dx.doi.org/10.3390/s20102807.
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A novel and compact interferometric refractive index (RI) point sensor is developed using hollow-core photonic crystal fiber (HC-PCF) and experimentally demonstrated for high sensitivity detection and measurement of pure gases. To construct the device, the sensing element fiber (HC-PCF) was placed between two single-mode fibers with airgaps at each side. Great measurement repeatability was shown in the cyclic test for the detection of various gases. The RI sensitivity of 4629 nm/RIU was demonstrated in the RI range of 1.0000347–1.000436 for the sensor with an HC-PCF length of 3.3 mm. The sensitivity of the proposed Mach–Zehnder interferometer (MZI) sensor increases when the length of the sensing element decreases. It is shown that response and recovery times of the proposed sensor inversely change with the length of HC-PCF. Besides, spatial frequency analysis for a wide range of air-gaps revealed information on the number and power distribution of modes. It is shown that the power is mainly carried by two dominant modes in the proposed structure. The proposed sensors have the potential to improve current technology’s ability to detect and quantify pure gases.
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Zhou, Wenjun, Xi Qin, Ming Lv, Lifeng Qiu, Zhongjiang Chen, and Fan Zhang. "Design of a New Type of In-Hole Gold-Coated High-Performance Quasi-PCF Sensor Enhanced with Surface Plasmon Resonance." Coatings 13, no. 7 (2023): 1261. http://dx.doi.org/10.3390/coatings13071261.
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With the development of aerospace, deep-sea exploration and other technologies, the demand for anti-electromagnetic, high-sensitivity and miniaturized sensors is increasingly urgent. In this paper, a model of a quasi-photonic crystal fiber (Q-PCF) refractive index (RI) sensor enhanced with surface plasmon resonance (SPR) is proposed. A stable gold film with a significant SPR effect is applied to the two identically sized and oppositely positioned air holes of the proposed sensor, and all air holes are filled with analyte. A detailed analysis of the mode characteristics, structural parameters and RI sensing performance of the sensor has been carried out using the finite element method. It has been shown that the maximum sensitivity (S) is 4977.59 nm/RIU in the RI range of 1.35–1.40, corresponding to a resolution (R) of 2.01 × 10−5 RIU and a figure of merit (FOM) of 160.36 RIU−1. The proposed Q-PCF sensor has unique fabrication advantages and outstanding sensing properties, providing a new idea for biosensing, complex environment monitoring and long-range measurement, and is of great practical value in the field of highly integrated sensing.
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Salim Neamah, Farah, and Hassan A Yasser. "Graphene-functionalized photonic crystal fibers for detecting the refractive index of a wide range of analyzes." Edelweiss Applied Science and Technology 8, no. 4 (2024): 1387–401. http://dx.doi.org/10.55214/25768484.v8i4.1513.
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This study looks into a new photonic crystal fiber (PCF) sensor covered in graphene that can detect changes in the analyte's refractive index (RI) in the COMSOL environment. The sensor operates by detecting a peak in light loss that varies in wavelength based on the RI of the analyte. Higher RI analytes shift the peak towards longer wavelengths. It is explored how many factors affect the sensor's performance, such as graphene's Fermi energy, the site inside the fiber, and the thickness of the gold layer. The location of graphene and its Fermi energy have a substantial influence on how the sensor responds. Interestingly, the resonant wavelength has a linear relationship with the RI of the analyte, which allows for precise RI calculation. Increasing gold thickness improves light-material interaction, but subsequent thickening has a detrimental impact, lowering sensor sensitivity. The appropriate thickness varies according to the material under consideration. Finally, the analysis determines the optimal arrangement of graphene for maximum sensitivity by completely covering the analyte holes in the PCF. By finding the right balance between these factors, the suggested sensor can have both high spectral sensitivity and low sensor resolution.
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Mohan, Devika, S. Simitha, Vibin Ipe Thomas, and Jesly Jacob. "Theoretical modelling of Au and Ag hollow cylinders for high resolution refractive index sensing of bio-analytes and gases." IOP Conference Series: Materials Science and Engineering 1263, no. 1 (2022): 012003. http://dx.doi.org/10.1088/1757-899x/1263/1/012003.
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A highly sensitive yet simple plasmonic refractive index (RI) sensor consisting of Au trimer hollow nanocylinders surrounded by an Ag hollow nanocylinder is proposed with a wide range of applications in the near IR range. The plasmonic behaviour of the structure is studied by analysing the absorption cross-section on illumination by electromagnetic (EM) wave using the finite element method (FEM). Nanoscale detections can be realized by using the shift in resonance wavelength of localized surface plasmon resonance (LSPR) in response to the change in RI. The optimized RI sensor gives a maximum sensitivity of 2545.4 nm/RIU, figure of merit (FOM) of 43.90 RIU−1 and sensor resolution of the order of 10−5 RIU. The proposed sensor can detect even small variations in RI of the order of 10−5 RIU with a sensitivity of 1998 nm/RIU. With the observed high sensitivity, resolution and quality, the sensor can contribute a lot to health-care applications and is found highly suitable for multiple detections covering broad range of RI including bio-analytes, chemicals, and gases.
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Chen, Chang, Zhang, Zhou, Lu, and Zhuang. "-1-5753907Highly Sensitive Plasmonic Sensor Based on a Dual-Side Polished Photonic Crystal Fiber for Component Content Sensing Applications." Nanomaterials 9, no. 11 (2019): 1587. http://dx.doi.org/10.3390/nano9111587.
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：A plasmonic sensor based on a dual-side polished photonic crystal fiber operating in a telecommunication wavelength range is proposed and investigated numerically by the finite element method (FEM). We study the effects of structural parameters on the sensor’s performance and analyze their tuning effects on loss spectra. As a result, two configurations are found when the analyte refractive index (RI) changes from 1.395 to 1.415. For configuration 1, an RI resolution of 9.39 × 10−6, an average wavelength sensitivity of 10,650 nm/RIU (the maximum wavelength sensitivity is 12,400 nm/RIU), an amplitude sensitivity of 252 RIU−1 and a linearity of 0.99692 are achieved. For configuration 2, the RI resolution, average wavelength sensitivity, amplitude sensitivity and linearity are 1.19 × 10−5, 8400 nm/RIU, 85 RIU−1 and 0.98246, respectively. The combination of both configurations can broaden the wavelength range for the sensing detection. Additionally, the sensor has a superior figure of merit (FOM) to a single-side polished design. The proposed sensor has a maximum wavelength sensitivity, amplitude sensitivity and RI resolution of the same order magnitude as that of existing sensors as well as higher linearity, which allows it to fulfill the requirements for modern sensing of being densely compact, amenable to integration, affordable and capable of remote sensing.
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Zhang, Jingao, Jinhui Yuan, Yuwei Qu, et al. "A Surface Plasmon Resonance-Based Photonic Crystal Fiber Sensor for Simultaneously Measuring the Refractive Index and Temperature." Polymers 14, no. 18 (2022): 3893. http://dx.doi.org/10.3390/polym14183893.
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In this paper, a surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) sensor is proposed for simultaneously measuring the refractive index (RI) and temperature. In the design, the central air hole and external surface of the proposed PCF are coated with gold films, and an air hole is filled with the temperature-sensitive material (TSM). By introducing the inner and outer gold films and TSM, the RI and temperature can be measured simultaneously at different wavelength regions. The simulation results show that the average wavelength sensitivities of the proposed SPR-based PCF sensor can reach 4520 nm/RIU and 4.83 nm/°C in the RI range of 1.35~1.40 and a temperature range of 20~60 °C, respectively. Moreover, because of using the different wavelength regions for sensing, the RI and temperature detections of the proposed SPR-based PCF sensor can be achieved independently. It is believed that the proposed SPR-based PCF RI and temperature sensor has important applications in biomedicine and in environmental science.
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Du, Wei, Lucas Miller, and Feng Zhao. "Numerical Study of Graphene/Au/SiC Waveguide-Based Surface Plasmon Resonance Sensor." Biosensors 11, no. 11 (2021): 455. http://dx.doi.org/10.3390/bios11110455.
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A new waveguide-based surface plasmon resonance (SPR) sensor was proposed and investigated by numerical simulation. The sensor consists of a graphene cover layer, a gold (Au) thin film, and a silicon carbide (SiC) waveguide layer on a silicon dioxide/silicon (SiO2/Si) substrate. The large bandgap energy of SiC allows the sensor to operate in the visible and near-infrared wavelength ranges, which effectively reduces the light absorption in water to improve the sensitivity. The sensor was characterized by comparing the shift of the resonance wavelength peak with change of the refractive index (RI), which mimics the change of analyte concentration in the sensing medium. The study showed that in the RI range of 1.33~1.36, the sensitivity was improved when the graphene layers were increased. With 10 graphene layers, a sensitivity of 2810 nm/RIU (refractive index unit) was achieved, corresponding to a 39.1% improvement in sensitivity compared to the Au/SiC sensor without graphene. These results demonstrate that the graphene/Au/SiC waveguide SPR sensor has a promising use in portable biosensors for chemical and biological sensing applications, such as detection of water contaminations (RI = 1.33~1.34), hepatitis B virus (HBV), and glucose (RI = 1.34~1.35), and plasma and white blood cells (RI = 1.35~1.36) for human health and disease diagnosis.
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Jiang, Meng, Ze-Ming Wang, Zhong-Ze Zhao, Kun Li, and Fu Yang. "Long-period fiber grating cascaded to thin-core fiber for simultaneous measurement of liquid refractive-index and temperature." Sensor Review 38, no. 1 (2018): 79–83. http://dx.doi.org/10.1108/sr-11-2016-0242.
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Purpose The purpose of this paper is to demonstrate a simple fiber sensor for simultaneous measurement of liquid refractive-index (RI) and temperature. Design/methodology/approach The sensor structure is formed by a long period fiber grating cascaded with a section of thin-core fiber. The long period fiber grating is fabricated on single mode fiber, followed by a section of 20-mm length thin-core fiber which is a modal interferometer. Findings Cladding mode interference between long period fiber grating and thin-core fiber modal interferometer is weak in the experimental investigation. Both of these two cladding mode type fiber devices are sensitive to surrounding RI and temperature. So the RI and temperature can be measured simultaneously by monitoring the spectral characteristics of the compound sensor. The sensitivity is calibrated and sensor matrix is provided in the experiment. Originality/value This proposed fiber sensor is simple, tough, cost-effective and suitable for discriminate the liquid RI and temperature with high sensitivity.
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Marć, Paweł, Monika Żuchowska, and Leszek R. Jaroszewicz. "Reflective Properties of a Polymer Micro-Transducer for an Optical Fiber Refractive Index Sensor." Sensors 20, no. 23 (2020): 6964. http://dx.doi.org/10.3390/s20236964.
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A polymer microtip manufactured at the end of a multi-mode optical fiber by using the photopolymerization process offers good reflective properties, therefore, it is applicable as an optical fiber sensor micro-transducer. The reflective properties of this microelement depend on the monomer mixture used, optical fiber type, and light source initiating polymerization. Experimental results have shown that a proper selection of these parameters has allowed the design of a new class of sensing structure which is sensitive to the refractive index (RI) changes of a liquid medium surrounding the microtip. An optical backscatter reflectometer was applied to test a group of micro-transducers. They were manufactured from two monomer mixtures on three different types of multi-mode optical fibers. They were polymerized by means of three optical light sources. Selected micro-transducers with optimal geometries were immersed in reference liquids with a known RI within the range of 1.3–1.7. For a few sensors, the linear dependences of return loss and RI have been found. The highest sensitivity was of around 208 dB/RIU with dynamic 32 dB within the range of 1.35–1.48. Sensing characteristics have minima close to RI of a polymer microelement, therefore, changing its RI can give the possibility to tune sensing properties of this type of sensor.
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Wang, Fengmin, Yong Wei, and Yanhong Han. "High-Sensitivity Refractive Index Sensor with Dual-Channel Based on Surface Plasmon Resonance Photonic Crystal Fiber." Sensors 24, no. 15 (2024): 5050. http://dx.doi.org/10.3390/s24155050.
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In order to achieve a high-precision synchronous detection of two different refractive index (RI) analytes, a D-type surface plasmon resonance (SPR) photonic crystal fiber (PCF) RI sensor based on two channels is designed in this paper. The sensor uses a D-shaped planar region of the PCF and a large circular air hole below the core as the sensing channels. Surface plasmon resonance is induced by applying a coating of gold film on the surface. The full-vector finite-element method (FEM) is used to optimize the structural parameters of the optical fiber, and the sensing characteristics are studied, including wavelength sensitivity, RI resolution, full width at half maximum (FWHM), figure of merit (FOM), and signal-to-noise ratio (SNR). The results show that the channel 1 (Ch 1) can achieve RI detection of 1.36–1.39 in the wavelength range of 1500–2600 nm, and the channel 2 (Ch 2) can achieve RI detection of 1.46–1.57 in the wavelength range of 2100–3000 nm. The two sensing channels can detect independently or simultaneously measure two analytes with different RIs. The maximum wavelength sensitivity of the sensor can reach 30,000 nm/RIU in Channel 1 and 9900 nm/RIU in Channel 2. The RI resolutions of the two channels are 3.54 × 10−6 RIU and 10.88 × 10−6 RIU, respectively. Therefore, the sensor realizes dual-channel high- and low-RI synchronous detection in the ultra-long wavelength band from near-infrared to mid-infrared and achieves an ultra-wide RI detection range and ultra-high wavelength sensitivity. The sensor has a wide application prospect in the fields of chemical detection, biomedical sensing, and water environment monitoring.
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Santos, Ana R., and Júlio C. Viana. "The Development of a Flexible Humidity Sensor Using MWCNT/PVA Thin Films." Nanomaterials 14, no. 20 (2024): 1653. http://dx.doi.org/10.3390/nano14201653.
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The exponential demand for real-time monitoring applications has altered the course of sensor development, from sensor electronics miniaturization, e.g., resorting to printing techniques, to low-cost, flexible and functional wearable materials. Humidity sensing has been used in the prevention and diagnosis of medical conditions, as well as in the assessment of physical comfort. This paper presents a resistive flexible humidity sensor composed of silver interdigitated electrodes (IDTs) screen printed onto polyimide film and an active layer of multiwall carbon nanotubes (MWCNT) dispersed in a water-soluble polymer, polyvinyl alcohol (PVA). Different MWCNT/PVA sensor sizes and MWCNT percentages are tested to study their effect on the initial electrical resistance (Ri) values and sensor response at different humidity percentages. The results show that the Ri values decrease with the increase in % MWCNT. The sensor size did not influence the sensor response, while the % MWCNT affected the sensor behavior upon relative humidity (RH) increments. The 1% MWCNT/PVA sensor showed the best response, reaching a relative electrical resistance, ΔR/R0, of 509% at 99% RH. Comparable with other reported sensors, the produced MWCNT/PVA flexible sensor is simpler, greener and shows a good sensitivity to humidity, being easily incorporated in wearable monitoring applications, from sports to medical fields.
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Yasli, Ahmet, and Huseyin Ademgil. "Multianalyte sensing analysis with multilayer photonic crystal fiber-based surface plasmon resonance sensor." Modern Physics Letters B 34, no. 33 (2020): 2050375. http://dx.doi.org/10.1142/s0217984920503753.
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In this work, we proposed multianalyte multichannel Photonic Crystal Fiber (PCF)-based Surface Plasmon Resonance sensor with gold- and silver-doped plasmonic layers. The Full Vectorial Finite Element Method (FV-FEM) with perfectly matched layers (PML) are employed for numerical analysis of the proposed sensor. The key propagation features, such as confinement loss, resonance condition, resolution, and sensitivity of the proposed sensor, have been reported for all possible refractive index variations. According to the spectral sensitivity analyses, the average sensitivities for fixed RI values are obtained as 4100 nm/RIU and 3820 nm/RIU for Ch1 and Ch2, respectively. On the other hand, results for varying RI values are obtained as 3600 nm/RIU and 3700 nm/RIU for Ch1 and Ch2, respectively. Moreover, the maximum average sensitivity of proposed sensor reaches to 4250 nm/RIU for varying RI at Ch2 and 4200 nm/RIU for varying RI at Ch1.
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Han, Haixia, Donglian Hou, Lei Zhao, et al. "A Large Detection-Range Plasmonic Sensor Based on An H-Shaped Photonic Crystal Fiber." Sensors 20, no. 4 (2020): 1009. http://dx.doi.org/10.3390/s20041009.
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An H-shaped photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) sensor is proposed for detecting large refractive index (RI) range which can either be higher or lower than the RI of the fiber material used. The grooves of the H-shaped PCF as the sensing channels are coated with gold film and then brought into direct contact with the analyte, which not only reduces the complexity of the fabrication but also provides reusable capacity compared with other designs. The sensing performance of the proposed sensor is investigated by using the finite element method. Numerical results show that the sensor can work normally in the large analyte RI (na) range from 1.33 to 1.49, and reach the maximum sensitivity of 25,900 nm/RIU (RI units) at the na range 1.47–1.48. Moreover, the sensor shows good stability in the tolerances of ±10% of the gold-film thickness.
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Zhao, Hongxia, Feng Wang, Zhaojia Han, Peihong Cheng, and Yong Wang. "Simultaneous measurement of temperature and refractive index based on plastic optical fiber knots and F–P interferometer." Measurement Science and Technology 35, no. 1 (2023): 015138. http://dx.doi.org/10.1088/1361-6501/ad042c.
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Abstract A reflective sensor based on F–P interferometer (FPI) and plastic optical fiber (POF) knots is proposed for simultaneously measuring the temperature and refractive index (RI). The FPI is fabricated by curing a polyvinyl chloride film on the end of a POF, and it is used to detect the temperature shifts. Meanwhile, the high sensitivity measurement of RI of the glucose solution is realized based on the POF knots. Finally, the RI and temperature are detected simultaneously with the help of the wavelength and reflected light intensity of an interference peak. The experimental results indicate that the proposed sensor achieves a maximum RI sensitivity of 2381.73%/RIU in the RI range of 1.33–1.374, and it can detect temperature simultaneously. The maximum relative deviations between the measured results and actual values of RI and temperature are only 0.038% and 2.76% respectively, and they have good repeatability. Furthermore, the proposed sensor has potential applications in biochemistry and food safety monitoring due to the unmodified and simple preparation process.
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Prasetya, Andinar Putri, and Riris Loisa. "Strategi Komunikasi Kampanye Budaya Sensor Mandiri Lembaga Sensor Film Republik Indonesia di Media Sosial TikTok." Prologia 9, no. 1 (2025): 139–46. https://doi.org/10.24912/pr.v9i1.33211.
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The Indonesian Film Censorship Board (LSF) plays a crucial role in educating the public about the importance of selecting age-appropriate content through the National Movement for Independent Censorship Culture. This study analyzes LSF's communication strategies in promoting this culture on the social media platform TikTok. Utilizing public communication theory, the research employs a qualitative approach, including in-depth interviews with LSF’s Public Relations team and direct observation. The findings indicate that LSF has successfully implemented an effective communication strategy. The campaign content, which provides information and knowledge about Independent Censorship Culture, has been effective in raising public awareness. Overall, the study concludes that LSF’s campaign on TikTok has made a positive contribution to enhancing the public's understanding of the importance of selecting age-appropriate content in line with classification standards. Lembaga Sensor Film (LSF) RI berperan penting dalam mengedukasi masyarakat mengenai pemilihan tontonan yang sesuai usia melalui Gerakan Nasional Budaya Sensor Mandiri. Penelitian ini menganalisis strategi komunikasi LSF RI dalam mengkampanyekan budaya tersebut di media sosial TikTok. Menggunakan teori komunikasi publik, penelitian ini dilakukan secara kualitatif dengan wawancara mendalam bersama Tim Publikasi LSF RI dan observasi langsung. Hasil penelitian menunjukkan bahwa LSF RI berhasil menerapkan strategi komunikasi yang efektif, dengan konten kampanye yang menyajikan informasi dan pengetahuan mengenai Budaya Sensor Mandiri. Konten ini dianggap berhasil meningkatkan kesadaran masyarakat akan pentingnya memilih tontonan yang sesuai dengan klasifikasi usia. Secara keseluruhan, penelitian ini menyimpulkan bahwa kampanye LSF RI di TikTok memberikan kontribusi positif dalam memperluas pemahaman publik tentang pentingnya sensor film dan pengawasan tontonan berdasarkan usia.
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Su, Ning, Wei Luo, Liusan Wang, Zhengyong Zhang, and Rujing Wang. "A Novel Dual-Wavelength Method for Evaluating Temperature Effect in Fiber-Optic SPR Sensors." Applied Sciences 11, no. 19 (2021): 9011. http://dx.doi.org/10.3390/app11199011.
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The temperature effect is one of the critical factors to induce the resonance wavelength shift in fiber-optic surface plasmon resonance (SPR) sensors, which leads to the inaccuracy measurement of refractive index (RI) in practical applications. In this study, a novel dual-wavelength method is presented for fiber-optic SPR sensors to measure the changes of RI and temperature simultaneously in real time. A typical model of an SPR-based fiber optical sensor is constructed for theoretical analysis of temperature effect. Both the thermo-optic effect in the fiber core and phonon–electron scattering along with electron–electron scattering in the metal layer are studied systematically in the theoretical model. The linear and independent relationship, about the dependence of defined output signals on the RI and temperature, is validated by a theoretical calculation in specific dual wavelengths. A proof-of-concept experiment is conducted to demonstrate the capability of the presented dual-wavelength technique. The experimental results indicate that the presented dual-wavelength method is technically feasible and can be applied for practical application. Since the presented method only depends on the full advantages of the transfer spectrum data, it can be applied directly to the conventional single-channel fiber-optic SPR without any specific design structure of the sensor probe. The proposed method provides a new way to detect the RI under different thermal conditions and could lead to a better design for the fiber-optic SPR sensors.
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Xiao, Gongli, Kaifu Zhang, Yuting Yang, et al. "Graphene Oxide Sensitized No-Core Fiber Step-Index Distribution Sucrose Sensor." Photonics 7, no. 4 (2020): 101. http://dx.doi.org/10.3390/photonics7040101.
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By coating graphene oxide (GO) onto the surface no-core fiber (NCF), we designed a single-mode no-core single-mode (SNS) fiber Step-Index Distribution sucrose sensor. With wavelength demodulation and the beam propagation method (BPM), the sensor without a GO coating was studied in the low RI range of 1.33~1.389, and the high RI range of 1.389~1.4185. The experiments show that the RI sensitivity of the sensor respectively reaches 132.9 nm/RIU and 292.22 nm/RIU. Both the numerical simulation and the experiments are highly consistent with the theoretical analysis results. Especially, having coated GO on the NCF for sensitization, a high sensitivity was achieved for the response to sucrose concentration solutions. The sensor’s RI sensitivity was increased from 132.9 nm/RIU up to 1348.67 nm/RIU in the ultra-narrow range of 1.33 to 1.3385. This result provides a theoretical and experimental basis for the enrichment and development of sensor detection with a low threshold sucrose concentration.
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Tien, Chuen-Lin, Tzu-Chi Mao, and Chi-Yuan Li. "Lossy Mode Resonance Sensors Fabricated by RF Magnetron Sputtering GZO Thin Film and D-Shaped Fibers." Coatings 10, no. 1 (2020): 29. http://dx.doi.org/10.3390/coatings10010029.
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We demonstrate a new refractive index (RI) and salinity sensor based on a lossy mode resonance (LMR) effect which combines fiber-optic side-polishing and radio-frequency (RF) sputtering techniques. The side-polished fiber can enhance optical fibers to generate an evanescent field in sensing applications. Gallium-doped zinc oxide (GZO) thin films produce a high attenuation lossy mode resonance effect that permits a highly sensitive refractive index and salinity fiber sensor. GZO thin film was prepared by an RF magnetron sputtering method. The thickness of the D-shaped fiber sensing device was 74.7 μm, and a GZO film thickness of 67 nm was deposited on the polished surface of the D-shaped fiber to fabricate LMR type liquid salinity sensors. The sensitivity of 3637.8 nm/RIU was achieved in the RI range of 1.333 to 1.392. To investigate the sensitivities of LMR salinity sensors, the NaCl solution salinities of 0%, 50%, 100%, 150%, 200%, and 250% were measured in this work. The experimental result shows that the sensitivity of the salinity sensor is 0.964 nm per salinity unit (SU).
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Romanchuk, V. V. "MODELLING AND RESEARCH OF THE PROPERTIES OF PLASTIC SUBSTRATES OF GAS SENSORS BASED ON SURFACE PLASMON RESONANCE." Optoelektronìka ta napìvprovìdnikova tehnìka 59 (September 18, 2024): 144–51. https://doi.org/10.15407/iopt.2024.59.144.
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Gas sensors based on surface plasmon resonance (SPR) are used in many areas of research (biological, chemical, medical, etc.), but such research is still quite expensive. Analysis of literary sources shows that special optical glass, in particular BK-7 or SF-11, is most often used as the substrate material for the sensitive element. These materials are expensive and require complex processing technologies. The use of plastic as a substrate material is a promising approach. Numerical mathematical modeling shows that the position of the SPR angles and the sensitivity of the sensor depend on the refractive index (RI) of the substrate material. The angles shift to a larger side when the RI of the substrate decreases and also depend on the selected laser wavelength. For a laser with a wavelength of 650 nanometers, the angles shift from 41.28° to 48.08° when the RI of the material decreases. For the 850 nanometer laser, the angle shift is smaller: from 40.31° to 46.67°. The angle shift for 650 nanometers is larger, resulting in higher sensitivity. Also, the sensitivity of the sensor depends on the magnitude of the change in the RI of the gas medium. For a 650 nanometer laser, the difference is from 55.30 degrees per refractive index unit (deg./RIU) to 60.54 deg./RIU for polycarbonate and from 70.38 deg./RIU to 81.28 deg./RIU for polydimethylsiloxane. For the 850 nanometer laser, this difference ranges from 50.90 deg./RIU to 54.67 deg./RIU for polycarbonate and from 63.86 deg./RIU to 71.63 deg./RIU for polydimethylsiloxane. As a result of the study, it is shown that the use of a material with a lower RI increases the sensitivity of the gas sensor, which expands the range of its applications. The sensitive element on the polydimethylsiloxane substrate increases the sensitivity of the gas sensor by 17% compared to the gold film on the BK-7 glass substrate. In this way, the expediency of using polydimethylsiloxane as a substitute for more expensive optical glass as a substrate material for the sensitive element of gas environment sensors based on SPR has been established.
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Noman, Abdullah Al, Emranul Haque, Md Anwar Hossain, Nguyen Hoang Hai, Yoshinori Namihira, and Feroz Ahmed. "Sensitivity Enhancement of Modified D-Shaped Microchannel PCF-Based Surface Plasmon Resonance Sensor." Sensors 20, no. 21 (2020): 6049. http://dx.doi.org/10.3390/s20216049.
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In this work, a highly sensitive dual-core configured microchannel-based plasmonic refractive index (RI) sensor was investigated, which can be used for low RI detection. Both the sensing layer and the plasmonic material layer were built outside of the fiber design to detect the surrounding medium’s RI changes. Additionally, the effects of different plasmonic materials gold (Au), silver (Ag), and copper (Cu) toward sensitivity were investigated for the same structure. An adhesive agent was used in this work, titanium dioxide (TiO2), and was coated on top of the plasmonic material to prevent the oxidation of Ag and Cu. The coupling strength between the fundamental mode and the surface plasmon polariton (SPP) mode was observed to be very strong due to the TiO2 adhesive agent. With a resolution of 7.41 × 10−7 RIU, maximum wavelength sensitivity (WS) of 135,000 nm/RIU and amplitude sensitivity (AS) of 3239 RIU−1 were achieved using the proposed sensor while using Au as a plasmonic material for an analyte RI range of 1.29–1.39. A detailed study of relevant literature revealed that the achieved wavelength sensitivity for plasmonic material gold (Au) is the highest among reported photonic crystal fiber (PCF)-surface plasmon resonance (SPR) sensors to date.
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Teng, Chuanxin, Rui Min, Jie Zheng, et al. "Intensity-Modulated Polymer Optical Fiber-Based Refractive Index Sensor: A Review." Sensors 22, no. 1 (2021): 81. http://dx.doi.org/10.3390/s22010081.
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The simple and highly sensitive measurement of the refractive index (RI) of liquids is critical for designing the optical instruments and important in biochemical sensing applications. Intensity modulation-based polymer optical fiber (POF) RI sensors have a lot of advantages including low cost, easy fabrication and operation, good flexibility, and working in the visible wavelength. In this review, recent developments of the intensity modulation POF-based RI sensors are summarized. The materials of the POF and the working principle of intensity modulation are introduced briefly. Moreover, the RI sensing performance of POF sensors with different structures including tapered, bent, and side-polished structures, among others, are presented in detail. Finally, the sensing performance for different structures of POF-based RI sensors are compared and discussed.
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Guo, Penglai, Huanhuan Liu, Zhitai Zhou, et al. "Spatially Modulated Fiber Speckle for High-Sensitivity Refractive Index Sensing." Sensors 23, no. 15 (2023): 6814. http://dx.doi.org/10.3390/s23156814.
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A fiber speckle sensor (FSS) based on a tapered multimode fiber (TMMF) has been developed to measure liquid analyte refractive index (RI) in this work. By the lateral and axial offset of input light into TMMF, several high-order modes are excited in TMMF, and the speckle pattern is spatially modulated, which affects an asymmetrical speckle pattern with a random intensity distribution at the output of TMMF. When the TMMF is immersed in the liquid analyte with RI variation, it influences the guided modes, as well as the mode interference, in TMMF. A digital image correlations method with zero-mean normalized cross-correlation coefficient is explored to digitize the speckle image differences, analyzing the RI variation. It is found that the lateral- and axial-offsets-induced speckle sensor can enhance the RI sensitivity from 6.41 to 19.52 RIU−1 compared to the one without offset. The developed TMMF speckle sensor shows an RI resolution of 5.84 × 10−5 over a linear response range of 1.3164 to 1.3588 at 1550 nm. The experimental results indicate the FSS provides a simple, efficient, and economic approach to RI sensing, which exhibits an enormous potential in the image-based ocean-sensing application.
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Yin, Zhiyong, Xili Jing, Yuhui Feng, Zhigang Gao, Biao Wu, and Chengjun Wang. "Refractive index and temperature dual parameter sensor based on a twin-core photonic crystal fiber." Journal of Physics D: Applied Physics 55, no. 15 (2022): 155108. http://dx.doi.org/10.1088/1361-6463/ac472b.
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Abstract A twin-core photonic crystal fiber sensor is proposed for measuring liquid refractive index (RI) and temperature simultaneously. The air holes of the sensor are arranged in a hexagonal pattern, and two planes are introduced by polishing in the cladding. On one side of the plane, the gold film is deposited for RI measurement, and on the other side, the gold film and polydimethylsiloxane are deposited for temperature measurement. We analyzed its sensing characteristics by using the finite element method. The numerical results show that the two channels for measuring RI and temperature have no mutual interference and the arrangement reduces the complexity of the sensing measurement. The maximum spectral sensitivity of the sensor is 20 000 nm/RIU and 9.2 nm °C−1, respectively, when the liquid RI is in the range of 1.36–1.42 and the temperature is in the range of 0 °C–50 °C. The results also show the sensing accuracy was not very sensitive to the change of structural parameters, which makes the sensor very easy to fabricate. Our work is very helpful for implementation of a high sensitivity, easy fabrication and real-time multi-parameter surface plasmon resonance sensor.
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Terentyev V.S. and Simonov V.A. "Experimental implementation of a spectral refractive index sensor based on a reflection interferometer." Optics and Spectroscopy 130, no. 12 (2022): 1628. http://dx.doi.org/10.21883/eos.2022.12.55253.3780-22.
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Experimental study of the sensor in the Kretschmann optical scheme, in which the sensitive element is a reflection interferometer (RI) for the oblique incidence of light, is presented for the first time. A brief theory of RI is given. The experimental sample was used to measure the refractive index of the residual atmosphere in a vacuum chamber during its pumping. The high Q-factor of the RI resonator made it possible to obtain a fairly narrow spectral maximum with a width of 1.7 nm. The spectral sensitivity of the sensor was 1000 nm/RIU and the quality parameter was 529 RIU-1, it was also demonstrated that resolution of 6.5·10-8 RIU can be achieved. Proposals for further improvement of the sensor characteristics are formulated. Keywords: reflection interferometer, total internal reflection, refractive index sensor.
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Chen, Nan, Min Chang, Xinglian Lu, Jun Zhou, and Xuedian Zhang. "Photonic Crystal Fiber Plasmonic Sensor Based on Dual Optofluidic Channel." Sensors 19, no. 23 (2019): 5150. http://dx.doi.org/10.3390/s19235150.
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A hexagonal photonic crystal fiber (PCF) sensor with a dual optofluidic channel based on surface plasmon resonance (SPR) effect is proposed. The sensor characteristic is numerically explored by software integrated with the finite element method (FEM). The numerical results show that, when the analyte refractive index (RI) varies from 1.32 to 1.38, high linearity between resonance wavelength and analyte RI is obtained and the value of adjusted R2 is up to 0.9993. Simultaneously, the proposed sensor has maximum wavelength sensitivity (WS) of 5500 nm/RIU and maximum amplitude sensitivity (AS) of 150 RIU−1, with an RI resolution of 1.82 × 10−5 RIU. Besides, owing to a simple structure and good tolerance of the proposed sensor, it can be easily fabricated by means of existing technology. The proposed sensor suggests promising applications in oil detection, temperature measurement, water quality monitoring, bio-sensing, and food safety.
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Li, Xiang, and Haifeng Zhang. "High-Sensitivity Janus Sensor Enabled by Multilayered Metastructure Based on the Photonic Spin Hall Effect and Its Potential Applications in Bio-Sensing." Sensors 24, no. 17 (2024): 5796. http://dx.doi.org/10.3390/s24175796.
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The refractive index (RI) of biological tissues is a fundamental material parameter that characterizes how light interacts with tissues, making accurate measurement of RI crucial for biomedical diagnostics and environmental monitoring. A Janus sensor (JBS) is designed in this paper, and the photonic spin Hall effect (PSHE) is used to detect subtle changes in RI in biological tissues. The asymmetric arrangement of the dielectric layers breaks spatial parity symmetry, resulting in significantly different PSHE displacements during the forward and backward propagation of electromagnetic waves, thereby realizing the Janus effect. The designed JBS can detect the RI range of 1.3~1.55 RIU when electromagnetic waves are incident along the +z-axis, with a sensitivity of 96.29°/refractive index unit (RIU). In the reverse direction, blood glucose concentrations are identified by the JBS, achieving a sensitivity of 18.30°/RIU. Detecting different RI range from forward and backward scales not only overcomes the limitation that single-scale sensors can only detect a single RI range, but also provides new insights and applications for optical biological detection through high-sensitivity, label-free and non-contact detection.
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Pevec, Simon, Janez Kunavar, Vedran Budinski, Matej Njegovec, and Denis Donlagic. "An All-Fiber Fabry–Pérot Sensor for Emulsion Concentration Measurements." Sensors 23, no. 4 (2023): 1905. http://dx.doi.org/10.3390/s23041905.
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This paper describes a Fabry–Pérot sensor-based measuring system for measuring fluid composition in demanding industrial applications. The design of the sensor is based on a two-parametric sensor, which enables the simultaneous measurement of temperature and refractive index (RI). The system was tested under real industrial conditions, and enables temperature-compensated online measurement of emulsion concentration with a high resolution of 0.03 Brix. The measuring system was equipped with filtering of the emulsion and automatic cleaning of the sensor, which proved to be essential for successful implementation of a fiber optic RI sensor in machining emulsion monitoring applications.
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Du, Zhenhua, and Huilong Liu. "Mid-infrared refractive index photonic crystal fiber sensor based on surface plasmon resonance for ultra-high sensitivity." Laser Physics 33, no. 1 (2022): 016201. http://dx.doi.org/10.1088/1555-6611/aca4ca.
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Abstract An ultra-high sensitivity photonic crystal fiber mid-infrared refractive index (RI) sensor based on surface plasmon resonance is proposed, whose properties are investigated by the finite element method. Gold can be utilized to create excitation between the fundamental mode and surface plasmon polaritons mode. The simulation results indicate that, at the wavelength of 1.7–4.0 μm, the proposed sensor could detect a RI in the range of 1.00–1.31, a maximum sensitivity of 37 000 nm RIU−1, and an optimal resolution of 2.70 × 10−6 RIU is achieved. The result of curve fitting is 0.98185. The proposed mid-infrared RI sensor plays an important role in organic chemistry detection, medical detection, and related fields.
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Chen, Nan, Min Chang, Xinglian Lu, Jun Zhou, and Xuedian Zhang. "Numerical Analysis of Midinfrared D-Shaped Photonic-Crystal-Fiber Sensor Based on Surface-Plasmon-Resonance Effect for Environmental Monitoring." Applied Sciences 10, no. 11 (2020): 3897. http://dx.doi.org/10.3390/app10113897.
Full textAbstract:
An exciting prospect for the sensing community is the potential of midinfrared fiber sensors. Taking advantage of the design flexibility of photonic crystal fiber and the high excitation loss of gold layers, a high-performance midinfrared D-shaped sensor based on the surface-plasmon-resonance effect was designed and numerically investigated by a mature finite-element tool. Numerical results showed that the designed fiber is especially suitable for sensing. In an operating wavelength ranging from 2.9 to 3.6 μm, maximal wavelength sensitivity of 11,500 nm/refractive index unit (RIU) and a maximal refractive index (RI) resolution of 8.7 × 10−6 RIU were obtained by the wavelength-interrogation method when analyte RI varied from 1.36 to 1.37. Maximal amplitude sensitivity of 230 RIU−1 was obtained by the amplitude-interrogation method with a high linearity of 0.99519 and an adequate figure of merit of 142. Additionally, the sensor had good fabrication tolerance. Our sensor is a promising candidate for environmental monitoring.
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Liu, Min, Xu Yang, Bingyue Zhao, Jingyun Hou, and Ping Shum. "Square array photonic crystal fiber-based surface plasmon resonance refractive index sensor." Modern Physics Letters B 31, no. 36 (2017): 1750352. http://dx.doi.org/10.1142/s0217984917503523.
Full textAbstract:
Based on surface plasmon resonance (SPR), a novel refractive index (RI) sensor comprising a square photonic crystal fiber (PCF) is proposed to realize the detection of the annular analyte. Instead of hexagon structure, four large air-holes in a square array are introduced to enhance the sensitivity by allowing two polarization directions of the core mode to be more sensitive. The gold is used as the only plasmonic material. The design purpose is to reduce the difficulty in gold deposition and enhance the RI sensitivity. The guiding properties and the effects of the parameters on the performance of the sensor are numerically investigated by the Finite Element Method (FEM). By optimizing the structure, the sensor can exhibit remarkable sensitivity up to 7250 nm/RIU and resolution of [Formula: see text] RIU with only one plasmonic material, which is very competitive compared with the other reported externally coated and single-layer coated PCF-based SPR (PCF–SPR) sensors, to our best knowledge.
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Teng, Chuanxin, Shiyuan Ying, Rui Min, et al. "Side-Polish Plastic Optical Fiber Based SPR Sensor for Refractive Index and Liquid-Level Sensing." Sensors 22, no. 16 (2022): 6241. http://dx.doi.org/10.3390/s22166241.
Full textAbstract:
In this work, a simple side-polish plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed and demonstrated for simultaneous measurement of refractive index (RI) and liquid level. The effects of side-polish depths on the sensing performance were studied. The experimental results show that the SPR peak wavelength will be changed as the RI changes, and the SPR peak intensity will be changed with the liquid level variation. By monitoring the changes in peak wavelength and intensity, the RI and liquid level can be detected simultaneously. Experimental results show that an RI sensitivity of 2008.58 nm/RIU can be reached at an RI of 1.39. This sensor has the advantages of simple structure and low cost, which has a good prospect in the field of biochemical sensing.
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Ramola, Ayushman, Amit Kumar Shakya, and Arik Bergman. "Finite Element Method-Based Modeling of a Novel Square Photonic Crystal Fiber Surface Plasmon Resonance Sensor with a Au–TiO2 Interface and the Relevance of Artificial Intelligence Techniques in Sensor Optimization." Photonics 12, no. 6 (2025): 565. https://doi.org/10.3390/photonics12060565.
Full textAbstract:
This research presents a novel square-shaped photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) sensor, designed using the external metal deposition (EMD) technique, for highly sensitive refractive index (RI) sensing applications. The proposed sensor operates effectively over an RI range of 1.33 to 1.37 and supports both x- polarized and y-polarized modes. It achieves a wavelength sensitivity of 15,800 nm/RIU and 14,300 nm/RIU, and amplitude sensitivities of 11,584 RIU−1 and 11,007 RIU−1, respectively, for the x-pol. and y-pol. The sensor also reports a resolution in the order of 10−6 RIU and a strong linearity of R2 ≈ 0.97 for both polarization modes, indicating its potential for precision detection in complex sensing environments. Beyond the sensor’s structural and performance innovations, this work also explores the future integration of artificial intelligence (AI) into PCF-SPR sensor design. AI techniques such as machine learning and deep learning offer new pathways for sensor calibration, material optimization, and real-time adaptability, significantly enhancing sensor performance and reliability. The convergence of AI with photonic sensing not only opens doors to smart, self-calibrating platforms but also establishes a foundation for next-generation sensors capable of operating in dynamic and remote applications.