Log in

Relevant bibliographies by topics / Wavefront correction / Journal articles

To see the other types of publications on this topic, follow the link: Wavefront correction.

Journal articles on the topic 'Wavefront correction'

Author: Grafiati

Published: 4 June 2021

Last updated: 31 January 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Wavefront correction.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Qiu, Xuejing, Tao Cheng, Lingxi Kong, Shuai Wang, and Bing Xu. "A Single Far-Field Deep Learning Adaptive Optics System Based on Four-Quadrant Discrete Phase Modulation." Sensors 20, no. 18 (September 8, 2020): 5106. http://dx.doi.org/10.3390/s20185106.

Full text

Abstract:

In adaptive optics (AO), multiple different incident wavefronts correspond to a same far-field intensity distribution, which leads to a many-to-one mapping. To solve this problem, a single far-field deep learning adaptive optics system based on four-quadrant discrete phase modulation (FQDPM) is proposed. Our method performs FQDPM on an incident wavefront to overcome this many-to-one mapping, then convolutional neural network (CNN) is used to directly predict the wavefront. Numerical simulations indicate that the proposed method can achieve precise high-speed wavefront correction with a single far-field intensity distribution: it takes nearly 0.6ms to complete wavefront correction while the mean root mean square (RMS) of residual wavefronts is 6.3% of that of incident wavefronts, and the Strehl ratio of the far-field intensity distribution increases by 5.7 times after correction. In addition, the experiment results show that mean RMS of residual wavefronts is 6.5% of that of incident wavefronts and it takes nearly 0.5 ms to finish wavefront reconstruction, which verifies the correctness of our proposed method.

APA, Harvard, Vancouver, ISO, and other styles

2

Zhang, Hong Xin, and Xiao Xi Xu. "High-Resolution Correction of Arbitrary Wavefront Aberration Using Liquid Crystal Spatial Light Modulator." Applied Mechanics and Materials 121-126 (October 2011): 877–81. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.877.

Full text

Abstract:

Wavefront correction plays significant role in some fields like astronomical observation, laser processing and medical imaging, etc. Liquid crystal spatial light modulator ( LC SLM) is an ideal device for high-resolution wavefront correction because of its low cost, low consumption, large number of pixels and independent programming control of each unit. It is researched experimentally that LC SLM is used as a wavefront correction device and corrects arbitrary wavefront aberration. Wavefront correction is performed based on phase conjugation and periodic phase modulation with modulo-2π. The experimental results show that the PV value of the irregular wavefront aberration is 1.56λ, RMS value is 0.25 and Strehl ratio is 0.08 before correction, but the PV value of the residual aberration is reduced to 0.26λ, RMS value is 0.02 and Strehl ratio is increased to 0.97 which is approximated diffraction limit after correction. It is proved to be feasible and effective that LC SLM is used to the high-precision and high-resolution wavefront correction.

APA, Harvard, Vancouver, ISO, and other styles

3

Zheng, Yamin, Ming Lei, Shibing Lin, Deen Wang, Qiao Xue, and Lei Huang. "Filtered Influence Function of Deformable Mirror for Wavefront Correction in Laser Systems." Photonics 8, no. 10 (September 23, 2021): 410. http://dx.doi.org/10.3390/photonics8100410.

Full text

Abstract:

An influence function filtering method (IFFM) is presented to improve the wavefront correction capability in laser systems by curbing the correction performance degradation resulted from the IF measurement noise. The IFFM is applied to the original measured IF. The resulting filtered IF is then used to calculate the wavefront control signal in each iteration of the closed-loop correction. A theoretical wavefront correction analysis model (CAM) is built. The impact of the IF measurement noise as well as the improvement of the IFFM on the wavefront correction capability are analyzed. A simulation is set up to analyze the wavefront correction capability of the filtered IF using Zernike mode aberrations. An experiment is carried out to study the effectiveness of the IFFM under practical conditions. Simulation and experimental results indicate that the IFFM could effectively reduce the negative effect of the measurement noise and improve the wavefront correction capability in laser systems. The IFFM requires no additional hardware and does not affect the correction speed.

APA, Harvard, Vancouver, ISO, and other styles

4

Dhamgaye, Vishal, David Laundy, Sara Baldock, Thomas Moxham, and Kawal Sawhney. "Correction of the X-ray wavefront from compound refractive lenses using 3D printed refractive structures." Journal of Synchrotron Radiation 27, no. 6 (October 19, 2020): 1518–27. http://dx.doi.org/10.1107/s1600577520011765.

Full text

Abstract:

A refractive phase corrector optics is proposed for the compensation of fabrication error of X-ray optical elements. Here, at-wavelength wavefront measurements of the focused X-ray beam by knife-edge imaging technique, the design of a three-dimensional corrector plate, its fabrication by 3D printing, and use of a corrector to compensate for X-ray lens figure errors are presented. A rotationally invariant corrector was manufactured in the polymer IP-STM using additive manufacturing based on the two-photon polymerization technique. The fabricated corrector was characterized at the B16 Test beamline, Diamond Light Source, UK, showing a reduction in r.m.s. wavefront error of a Be compound refractive Lens (CRL) by a factor of six. The r.m.s. wavefront error is a figure of merit for the wavefront quality but, for X-ray lenses, with significant X-ray absorption, a form of the r.m.s. error with weighting proportional to the transmitted X-ray intensity has been proposed. The knife-edge imaging wavefront-sensing technique was adapted to measure rotationally variant wavefront errors from two different sets of Be CRL consisting of 98 and 24 lenses. The optical aberrations were then quantified using a Zernike polynomial expansion of the 2D wavefront error. The compensation by a rotationally invariant corrector plate was partial as the Be CRL wavefront error distribution was found to vary with polar angle indicating the presence of non-spherical aberration terms. A wavefront correction plate with rotationally anisotropic thickness is proposed to compensate for anisotropy in order to achieve good focusing by CRLs at beamlines operating at diffraction-limited storage rings.

APA, Harvard, Vancouver, ISO, and other styles

5

Yang, Huizhen, Zhen Zhang, and Jian Wu. "Performance Comparison of Wavefront-Sensorless Adaptive Optics Systems by Using of the Focal Plane." International Journal of Optics 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/985351.

Full text

Abstract:

The correction capability and the convergence speed of the wavefront-sensorless adaptive optics (AO) system are compared based on two different system control algorithms, which both use the information of focal plane. The first algorithm is designed through the linear relationship between the second moment of the aberration gradients and the masked far-field intensity distribution and the second is stochastic parallel gradient descent (SPGD), which is the most commonly used algorithm in wavefront-sensorless AO systems. A wavefront-sensorless AO model is established with a 61-element deformable mirror (DM) and a CCD. Performance of the two control algorithms is investigated and compared through correcting different wavefront aberrations. Results show that the correction ability of AO system based on the proposed control algorithm is obviously better than that of AO system based on SPGD algorithm when the wavefront aberrations increase. The time needed by the proposed control algorithm is much less than that of SPGD when the AO system achieves similar correction results. Additionally, the convergence speed of the proposed control algorithm is independent of the turbulence strength while the number of intensity measurements needed by SPGD increases as the turbulence strength magnifies.

APA, Harvard, Vancouver, ISO, and other styles

6

Applegate, Ray, David Atchison, Arthur Bradley, Adrian Bruce, Michael Collins, Jason Marsack, Scott Read, Larry N. Thibos, and Geunyoung Yoon. "Wavefront Refraction and Correction." Optometry and Vision Science 91, no. 10 (October 2014): 1154–55. http://dx.doi.org/10.1097/opx.0000000000000373.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Yamada, Jumpei, Takato Inoue, Nami Nakamura, Takashi Kameshima, Kazuto Yamauchi, Satoshi Matsuyama, and Makina Yabashi. "X-Ray Single-Grating Interferometry for Wavefront Measurement and Correction of Hard X-Ray Nanofocusing Mirrors." Sensors 20, no. 24 (December 21, 2020): 7356. http://dx.doi.org/10.3390/s20247356.

Full text

Abstract:

X-ray single-grating interferometry was applied to conduct accurate wavefront corrections for hard X-ray nanofocusing mirrors. Systematic errors in the interferometer, originating from a grating, a detector, and alignment errors of the components, were carefully examined. Based on the measured wavefront errors, the mirror shapes were directly corrected using a differential deposition technique. The corrected X-ray focusing mirrors with a numerical aperture of 0.01 attained two-dimensionally diffraction-limited performance. The results of the correction indicate that the uncertainty of the wavefront measurement was less than λ/72 in root-mean-square value.

APA, Harvard, Vancouver, ISO, and other styles

8

Nobis, Thomas. "Impact of Pupil Aberrations on Wavefront Manipulation." EPJ Web of Conferences 255 (2021): 03004. http://dx.doi.org/10.1051/epjconf/202125503004.

Full text

Abstract:

A systematic and quantitative analysis is given of the impact of pupil aberrations on the imaging performance in wavefront manipulation applications using adaptive optical elements. For the practical case of rotationally-symmetric types of wavefront corrections, such as defocus or spherical aberration, analytical expressions of the induced aberrations are derived including their pupil and field dependence. Each aberration is thereby related to the specific pupil aberration present at the adaptive element. The results can be used to specify the acceptable amount of pupil correction required for a specific magnitude and type of wavefront manipulation.

APA, Harvard, Vancouver, ISO, and other styles

9

Zhang, Zhentao, Nazim Bharmal, Tim Morris, and Yonghui Liang. "Laboratory quantification of a plenoptic wavefront sensor with extended objects." Monthly Notices of the Royal Astronomical Society 497, no. 4 (August 5, 2020): 4580–86. http://dx.doi.org/10.1093/mnras/staa2269.

Full text

Abstract:

ABSTRACT Adaptive optics (AO) is widely used in ground-based telescopes to compensate the effects of atmosphere distortion, and the wavefront sensor is a significant component in the AO systems. The plenoptic wavefront sensor has been proposed as an alternative wavefront sensor adequate for extended objects and wide field of views. In this paper, a experimental bench has been set up to investigate the slope measurement accuracy and closed-loop wavefront correction performance for extended objects. From the experimental results, it has been confirmed that plenoptic wavefront sensor is suitable for extended objects wavefront sensing with proper optical design. The slope measurements have a good linearity and accuracy when observing extended objects. The image quality is significantly improved after closed-loop correction. A method of global tip/tilt measurement using only plenoptic wavefront sensor frame is proposed in this paper, it is also a potential advantage of plenoptic wavefront sensor in extended objects wavefront sensing.

APA, Harvard, Vancouver, ISO, and other styles

10

Li, Jin, Luwei Wang, Yong Guo, Yangrui Huang, Zhigang Yang, Wei Yan, and Junle Qu. "Study on Aberration Correction of Adaptive Optics Based on Convolutional Neural Network." Photonics 8, no. 9 (September 8, 2021): 377. http://dx.doi.org/10.3390/photonics8090377.

Full text

Abstract:

The existence of aberrations has always been an important limiting factor in the imaging field. Especially in optical microscopy imaging, the accumulated aberration of the optical system and the biological samples distorts the wavefront on the focal plane, thereby reducing the imaging resolution. Here, we propose an adaptive optical aberration correction method based on convolutional neural network. By establishing the relationship between the Zernike polynomial and the distorted wavefront, with the help of the fast calculation advantage of an artificial intelligence neural network, the distorted wavefront information can be output in a short time for the reconstruction of the wavefront to achieve the purpose of improving imaging resolution. Experimental results show that this method can effectively compensate the aberrations introduced by the system, agarose and HeLa cells. After correcting, the point spread function restored the doughnut-shape, and the resolution of the HeLa cell image increased about 20%.

APA, Harvard, Vancouver, ISO, and other styles

11

Xu Zeshuai, 许泽帅, 羊毅 Yang Yi, 兰卫华 Lan Weihua, 穆海平 Mu Haiping, and 刘玉 Liu Yu. "Correction of Distorted Wavefront Based on Direct Wavefront Gradient Algorithm." Laser & Optoelectronics Progress 51, no. 4 (2014): 040101. http://dx.doi.org/10.3788/lop51.040101.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Hu, L., L. Xuan, D. Li, Z. Cao, Q. Mu, Y. Liu, Z. Peng, and X. Lu. "Wavefront correction based on a reflective liquid crystal wavefront sensor." Journal of Optics A: Pure and Applied Optics 11, no. 1 (December 30, 2008): 015511. http://dx.doi.org/10.1088/1464-4258/11/1/015511.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Steinberg, Bernard D. "A Discussion of Two Wavefront Aberration Correction Procedures." Ultrasonic Imaging 14, no. 4 (October 1992): 387–97. http://dx.doi.org/10.1177/016173469201400405.

Full text

Abstract:

This review paper discusses the basic properties of two adaptive signal processing procedures for dealing with weak scattering in a phased array transducer system. A fundamental improvement in the lateral resolution of ultrasonic echo scanners will result if the weight vector of a large phased array transducer can be modified to account for distortion in the propagation medium. Lateral resolution in most tissue is limited to a few mm by wavefront-distortion-induced sound-speed variations. One important wavefront-distortion source is scattering from local speed variations within large and reasonably homogeneous tissue beds such as the liver. Scattering disperses some energy from the beam and perturbs the wavefront, thereby distorting the image and limiting the resolution to the scale of the distortion. Often, such scattering is weak, meaning that most of the energy in the beam is unscattered. The total field at the receiving transducer is the vector sum of the unscattered and scattered fields. In weak scattering the unscattered field is dominant and the resultant field can be treated as the unscattered field plus a perturbation. The net effect is primarily a distorted phasefront, while the ampitude or modulus of the wavefront remains reasonably intact. Refraction and strong scattering affect the wavefront more severely and are less responsive to these algorithms.

APA, Harvard, Vancouver, ISO, and other styles

14

Wu, Fenxiang, Ende Li, Yi Xu, Jiayi Qian, Jiacheng Zhu, Jiabing Hu, Yang Zhao, et al. "Wavefront Correction in Vacuum of SULF-1PW Laser Beamline." Photonics 9, no. 11 (November 18, 2022): 872. http://dx.doi.org/10.3390/photonics9110872.

Full text

Abstract:

The focusing quality of high peak power lasers plays a crucial role in laser wakefield electron acceleration investigations. We report here an improvement in the focusing quality of the SULF-1PW laser beamline, planning to drive and generate 5~10 GeV electron beams. After the wavefront correction in vacuum with an adaptive optical system and the focusing with an f/56 off-axis parabolic mirror, near-diffraction-limited focal spots with a size of 52 × 54 μm2 at full width at half maximum are achieved, and the enclosed energy inside this size is ~36.6%. Consequently, the focused intensity of ~1.66 × 1019 W/cm2 can be achieved at 1 PW peak power. Moreover, we also examine the wavefront stability in air and vacuum, respectively. From the statistical analysis of 1900 shots of successive laser pulses at 1 Hz, we identify the wavefront fluctuation resulting from air turbulence and the better correction capacity in vacuum. This work demonstrates the importance and necessity of wavefront correction in vacuum for high peak power lasers.

APA, Harvard, Vancouver, ISO, and other styles

15

Zhang, Xiang. "Analyzing Output Phase Properties of Confocal Positive-Branch Laser Resonators by Use of Hartmann-Shack Sensor." Advanced Materials Research 282-283 (July 2011): 561–64. http://dx.doi.org/10.4028/www.scientific.net/amr.282-283.561.

Full text

Abstract:

The effect of intracavity aberrated perturbation on output mode structure properties of passive confocal unstable resonator is been experimentally researched by adopting H-S wavefront sensor and Zernike modal wavefront reconstruction on the basis of numerical simulation. Results show that intracavity tilted perturbation notablely affects outcoupled intensity distribution, and will also increase some high-order aberrations of beam phase properties. However, low-order Zernike tilt aberration is the main component when phase-tilted perturbation is introduced into the resonator. Defocus, astigmatism and coma aberration will all be brought, and also such high-order aberration included in wavefront will directly degrade output beam quality. When correction device of adaptive optics adopted for intracavity aberration correction, correction of tilted aberration should be considered firstly.

APA, Harvard, Vancouver, ISO, and other styles

16

Stonecipher, Karl, Joseph Parrish, and Megan Stonecipher. "Comparing wavefront-optimized, wavefront-guided and topography-guided laser vision correction." Current Opinion in Ophthalmology 29, no. 4 (July 2018): 277–85. http://dx.doi.org/10.1097/icu.0000000000000495.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Ke Xizheng, 柯熙政, and 韩柯娜 Han Kena. "Wavefront Simulation and Wavefront Correction of Liquid Crystal Spatial Light Modulator." Laser & Optoelectronics Progress 56, no. 5 (2019): 051403. http://dx.doi.org/10.3788/lop56.051403.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Wang, Yukun, Dayu Li, and Chengbin Jin. "Eigenmode Wavefront Decoupling Algorithm for LC–DM Adaptive Optics Systems." Applied Sciences 12, no. 15 (August 5, 2022): 7875. http://dx.doi.org/10.3390/app12157875.

Full text

Abstract:

To realize the decoupling control of the dual corrector of liquid crystal (LC)–deformable mirror (DM) adaptive optics (AO) systems and prevent the loss of correction ability induced by coupling aberrations, a wavefront decoupling method based on DM eigenmodes was proposed. The coupling relationship of two correctors was studied, and the distribution of aberrations corrected using the DM and LC was investigated. First, a DM eigenmode matrix was derived according to the DM influence function. Then, aberrations were decomposed according to the Strehl ratio, and the projection of the LC response matrix on the DM eigenmode matrix, that is, the coupling term, was derived. Before using the LC corrector, the coupling item was eliminated for the decoupling of the two correctors, and the decoupling effect was verified through simulations. Finally, a 2 m telescope LC–DM AO system was developed to validate the proposed method. The simulation and experimental results showed that the root mean square of the DM-corrected residual after 55 eigenmodes’ correction was 0.09 μm. After decoupling correction, the resolution of the 700–1700 nm wide band improved from 1.1 to 1 times the diffraction limit, which is 1.2 times better than that obtained using the traditional Zernike mode correction.

APA, Harvard, Vancouver, ISO, and other styles

19

Wu Jiali, 吴加丽, and 柯熙政 Ke Xizheng. "Adaptive Optics Correction of Wavefront Sensorless." Laser & Optoelectronics Progress 55, no. 3 (2018): 030103. http://dx.doi.org/10.3788/lop55.030103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Gall, Pierre Le, and Lionel Rosier. "EXACT WAVEFRONT CORRECTION IN ADAPTIVE OPTICS." IFAC Proceedings Volumes 38, no. 1 (2005): 748–53. http://dx.doi.org/10.3182/20050703-6-cz-1902.00525.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Gupta, Amita, Shailesh Kumar, Ranvir Singh, Monika Chaudhary, A. Meena, and V. Sarvanan. "Deformable Membrane Mirror for Wavefront Correction." Defence Science Journal 59, no. 6 (November 24, 2009): 590–94. http://dx.doi.org/10.14429/dsj.59.1563.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Smith, C. S., R. Marinică, A. J. den Dekker, M. Verhaegen, V. Korkiakoski, C. U. Keller, and N. Doelman. "Iterative linear focal-plane wavefront correction." Journal of the Optical Society of America A 30, no. 10 (September 13, 2013): 2002. http://dx.doi.org/10.1364/josaa.30.002002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Vasil'ev, A. A., A. F. Naumov, and V. I. Shmal'gauzen. "Wavefront correction by liquid-crystal devices." Soviet Journal of Quantum Electronics 16, no. 4 (April 30, 1986): 471–74. http://dx.doi.org/10.1070/qe1986v016n04abeh006221.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Yeminy, Tomer, and Ori Katz. "Guidestar-free image-guided wavefront shaping." Science Advances 7, no. 21 (May 2021): eabf5364. http://dx.doi.org/10.1126/sciadv.abf5364.

Full text

Abstract:

Optical imaging through scattering media is a fundamental challenge in many applications. Recently, breakthroughs such as imaging through biological tissues and looking around corners have been obtained via wavefront-shaping approaches. However, these require an implanted guidestar for determining the wavefront correction, controlled coherent illumination, and most often raster scanning of the shaped focus. Alternative novel computational approaches that exploit speckle correlations avoid guidestars and wavefront control but are limited to small two-dimensional objects contained within the “memory-effect” correlation range. Here, we present a new concept, image-guided wavefront shaping, allowing widefield noninvasive, guidestar-free, incoherent imaging through highly scattering layers, without illumination control. The wavefront correction is found even for objects that are larger than the memory-effect range, by blindly optimizing image quality metrics. We demonstrate imaging of extended objects through highly scattering layers and multicore fibers, paving the way for noninvasive imaging in various applications, from microscopy to endoscopy.

APA, Harvard, Vancouver, ISO, and other styles

25

Rukosuev, Alexey, Alexander Nikitin, Vladimir Toporovsky, Julia Sheldakova, and Alexis Kudryashov. "Real-Time Correction of a Laser Beam Wavefront Distorted by an Artificial Turbulent Heated Airflow." Photonics 9, no. 5 (May 17, 2022): 351. http://dx.doi.org/10.3390/photonics9050351.

Full text

Abstract:

This paper presents a FPGA-based closed-loop adaptive optical system with a bimorph deformable mirror for correction of the phase perturbation caused by artificial turbulence. The system’s operating frequency of about 2000 Hz is, in many cases, sufficient to provide the real-time mode. The results of the correction of the wavefront of laser radiation distorted by the airflow formed in the laboratory conditions with the help of a fan heater are presented. For detailed consideration, the expansion of the wavefront by Zernike polynomials is used with further statistical analysis based on the discrete Fourier transform. The result of the work is an estimation of the correction efficiency of the wavefront distorted by the turbulent phase fluctuations. The ability of the bimorph adaptive mirror to correct for certain aberrations is also determined. As a result, it was concluded that the adaptive bimorph mirrors, together with a fast adaptive optical system based on FPGA, can be used to compensate wavefront distortions caused by atmospheric turbulence in the real-time mode.

APA, Harvard, Vancouver, ISO, and other styles

26

RK, Sia, Ryan DS, Stutsman RD, Pasternak JF, Eaddy JB, Logan LA, Rivers BA, and Bower KS. "Astigmatic Outcomes after Wavefront-Guided and Wavefront-Optimized Refractive Surgeries for Myopia with Low to Moderate Cylinder." Current Trends in Ophthalmology 2, no. 1 (November 25, 2019): 183–92. http://dx.doi.org/10.18314/ctoy.v2i1.1921.

Full text

Abstract:

Purpose: To compare the efficacy and accuracy of wavefront-guided (WFG) and wavefront-optimized (WFO) PRK and LASIK for the treatment of myopia with low to moderate astigmatism.Methods: In this prospective cohort study, 215 active duty military service members (430 eyes, mean spherical equivalent -3.61 ± 1.53 D) electing either PRK or LASIK were randomized to undergo WFG or WFO treatment. Up to 12 months, postoperative visual outcomes following surgeries were compared between 4 treatment groups: WFG PRK, WFG LASIK, WFO PRK, and WFO LASIK for myopia with 0.25 to 0.50 D astigmatism (≤ 0.50 D cyl subgroup) and ≥ 0.75 D astigmatism (≥ 0.75 D cyl subgroup). High and low contrast visual acuities were assessed and vector analysis was performed.Results: At 12 months postoperatively, the surgically induced astigmatism, magnitude of error, correction and flattening indices were significantly different between treatment groups (P values ≤ 0.001) in the ≤ 0.50 D cyl subgroup. In ≥ the 0.75 D cyl subgroup, there were no significant differences in vector analysis parameters except for the magnitude of error and correction index (P values ≤ 0.010). The treatment groups were comparable in terms of postoperative uncorrected distance visual acuity, manifest spherical equivalent, and best-corrected low contrast visual acuity.Conclusions: No treatment modality showed consistent superiority in correcting low to moderate astigmatism. Overall, both PRK and LASIK using either wavefront-guided or wavefront-optimized laser platforms were similarly effective and accurate in treating myopia with a low to moderate amount of astigmatism.

APA, Harvard, Vancouver, ISO, and other styles

27

Rueckel, M., J. A. Mack-Bucher, and W. Denk. "Adaptive wavefront correction in two-photon microscopy using coherence-gated wavefront sensing." Proceedings of the National Academy of Sciences 103, no. 46 (November 6, 2006): 17137–42. http://dx.doi.org/10.1073/pnas.0604791103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Ghoreishi, Seyyed Mohammad, Afsaneh Naderibeni, Alireza Peyman, Akram Rismanchian, and Fatemeh Eslami. "Aspheric Profile versus Wavefront-Guided Ablation Photorefractive Keratectomy for the Correction of Myopia using the Allegretto Eye Q." European Journal of Ophthalmology 19, no. 4 (July 2009): 544–53. http://dx.doi.org/10.1177/112067210901900405.

Full text

Abstract:

Purpose To compare the results of photorefractive keratectomy (PRK) with Q-factor customized aspheric ablation and wavefront-guided customized ablation for correction of myopia compound with astigmatism. Methods Fifty-six patients were enrolled in this prospective controlled study. In each patient, one eye was randomly assigned for treatment with the Q-factor customized PRK (custom-Q study group) and the other eye treated with wavefront-guided customized PRK. Preoperative and 3-month postoperative manifest refraction, contrast sensitivity, visual acuity, aberrometry, and asphericity of the cornea were compared between the two groups. All eyes were treated with the Wavelight Eye-Q 400 Hz excimer laser in a single refractive surgery center by a single surgeon. Results Uncorrected visual acuity (UCVA) improved to 20/20 or more and 20/25 or more in 34 eyes (60.7%) and 56 eyes (100%), respectively, in the wavefront-guided ablation group and in 36 eyes (64.2%) and 54 eyes (96.4%) in the custom-Q ablation group. All eyes had UCVA of 20/40 or better. A total of 54 eyes (96.4%) in the wavefront-guided ablation group and 56 (100%) in the custom-Q ablation group had spherical equivalent (SE) within ±0.5 D. One eye in each group (2%) lost ≥ 2 lines of best-corrected visual acuity (BCVA). High order root mean square (RMS) in the wavefront-guided group was 0.3630±0.13 μm preoperatively and 0.427±0.17 at 3 months (p=0.2). In the custom-Q ablation group it was 0.329±0.092 preoperatively and 0.4730±0.181 at 3 months after PRK (p=0.08). Conclusions Regarding safety and refractive efficacy, custom-Q ablation profiles were clinically equivalent to wavefront-guided profiles in corrections of myopia up to −6.00 D and astigmatism up to 2.50 D.

APA, Harvard, Vancouver, ISO, and other styles

29

Nevzorov, A. A., and D. A. Stankevich. "A method of wavefront distortions correction for an atmospheric optical link with a small volume of information transmitted through a service channel." Computer Optics 44, no. 5 (October 2020): 848–51. http://dx.doi.org/10.18287/2412-6179-co-733.

Full text

Abstract:

The paper describes a method of wavefront distortion correction in a turbulent atmosphere, which allows reducing the volume of information transmitted through a service channel. The correction is carried out with a transparency whose phase mask is calculated by a simple three-layer neural network by intensity distribution obtained at the photoreceiver. The architecture of the network is constructed so that the amount of data transferred over the service channel is reduced to 30 parameters, using which a corrective mask is then constructed.

APA, Harvard, Vancouver, ISO, and other styles

30

Nishikawa, Jun, Yutaka Hayano, Naruhisa Takato, Motokazu Noguchi, Masanori Iye, Koh-Ichiro Morita, and Masato Ishiguro. "Minimum Redundant Aperture Masking Interferometry With Tip-Tilt Wavefront Correction." Symposium - International Astronomical Union 158 (1994): 296–98. http://dx.doi.org/10.1017/s0074180900107752.

Full text

Abstract:

We made aperture masking optical interferometry experiments using up to 30 apertures and with a tip-tilt correction of wavefront error. We examined the performance of minimum redundant configurations of 11–30 sub-apertures on the pupil plane mask. These configurations have two advantages; the redundancy noise is as small as realized in non-redundant masking method, and the uv-coverage is as high as in speckle interferometry enabling to get reconstructed images without mask exchange. We also examined the effect of tip-tilt wavefront correction within a telescope pupil in front of the aperture masking optics. The light coherency between sub-apertures was shown to increase by the correction.

APA, Harvard, Vancouver, ISO, and other styles

31

Allan, Bruce D. "Cochrane Corner: wavefront-guided laser vision correction." Eye 35, no. 9 (April 28, 2021): 2454–55. http://dx.doi.org/10.1038/s41433-021-01534-w.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Marsack, Jason D., Ayeswarya Ravikumar, Chi Nguyen, Anita Ticak, Darren E. Koenig, James D. Elswick, and Raymond A. Applegate. "Wavefront-Guided Scleral Lens Correction in Keratoconus." Optometry and Vision Science 91, no. 10 (October 2014): 1221–30. http://dx.doi.org/10.1097/opx.0000000000000275.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Waag, Robert C., Dong‐Lai Liu, Laura M. Hinkelman, and T. Douglas Mast. "Measurement and correction of ultrasonic wavefront distortion." Journal of the Acoustical Society of America 100, no. 4 (October 1996): 2646. http://dx.doi.org/10.1121/1.417807.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Liu Zhangwen, 刘章文, 周志强 Zhou Zhiqiang, and 李正东 Li Zhengdong. "Wavefront Correction Technology Based on Fuzzy Control." Laser & Optoelectronics Progress 54, no. 3 (2017): 030101. http://dx.doi.org/10.3788/lop54.030101.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Dyson, Harold, Ray Sharples, N. Dipper, and Gleb Vdovin. "Cryogenic wavefront correction using membrane deformable mirrors." Optics Express 8, no. 1 (January 1, 2001): 17. http://dx.doi.org/10.1364/oe.8.000017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Ren, Deqing, Gang Wang, and Xi Zhang. "Approach for deformable mirror wavefront error correction." Optical Engineering 58, no. 01 (January 8, 2019): 1. http://dx.doi.org/10.1117/1.oe.58.1.014102.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

South, Fredrick A., Kazuhiro Kurokawa, Zhuolin Liu, Yuan-Zhi Liu, Donald T. Miller, and Stephen A. Boppart. "Combined hardware and computational optical wavefront correction." Biomedical Optics Express 9, no. 6 (May 8, 2018): 2562. http://dx.doi.org/10.1364/boe.9.002562.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Zelenka, Claudius, and Reinhard Koch. "Improved wavefront correction for coherent image restoration." Optics Express 25, no. 16 (July 25, 2017): 18797. http://dx.doi.org/10.1364/oe.25.018797.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Zhu, Qing, and Bernard Steinberg. "Modeling and correction of incoherent wavefront distortion." International Journal of Imaging Systems and Technology 8, no. 3 (1997): 322–35. http://dx.doi.org/10.1002/(sici)1098-1098(1997)8:3<322::aid-ima10>3.0.co;2-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Mackay, Craig. "High-Resolution Imaging in the Visible with Faint Reference Stars on Large Ground-Based Telescopes." Journal of Astronomical Instrumentation 08, no. 04 (December 2019): 1950015. http://dx.doi.org/10.1142/s2251171719500156.

Full text

Abstract:

Astronomers working with faint targets will benefit greatly from improved image quality on current and planned ground-based telescopes. At present, most adaptive optic systems are targeted at the highest resolution with bright guide stars. We demonstrate a significantly new approach for measuring low-order wavefront errors by using a pupil-plane curvature wavefront sensor design. By making low order wavefront corrections, we can deliver significant improvements in image resolution in the visible on telescopes in the 2.5–8.2 m range on good astronomical sites. As a minimum, the angular resolution will be improved by a factor of 2.5–3 under any reasonable conditions and, with further correction and image selection, even sharper images may be obtained routinely. We re-examine many of the assumptions about what may be achieved with faint reference stars to achieve this performance. We show how our new design of curvature wavefront sensor combined with wavefront fitting routines based on radon transforms allow this performance to be achieved routinely. Simulations over a wide range of conditions match the performance already achieved in runs with earlier versions of the hardware described. Reference stars significantly fainter than I [Formula: see text]17[Formula: see text]m may be used routinely to produce images with a near diffraction limited core and halo much smaller than that delivered by natural seeing.

APA, Harvard, Vancouver, ISO, and other styles

41

Sharghi, Afshan. "Surgical Correction of Different Severities of Astigmatism Using Wavefront-Optimized Photorefractive Keratectomy." International Journal of Psychosocial Rehabilitation 24, no. 5 (May 30, 2020): 7489–505. http://dx.doi.org/10.37200/ijpr/v24i5/pr2020783.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Esposito, S., A. Puglisi, E. Pinna, G. Agapito, F. Quirós-Pacheco, J. P. Véran, and G. Herriot. "On-sky correction of non-common path aberration with the pyramid wavefront sensor." Astronomy & Astrophysics 636 (April 2020): A88. http://dx.doi.org/10.1051/0004-6361/201937033.

Full text

Abstract:

The paper deals with with the on-sky performance of the pyramid wavefront sensor-based Adaptive Optics (AO) systems. These wavefront sensors are of great importance, being used in all first light AO systems of the ELTs (E-ELT, GMT, and TMT), currently in design phase. In particular, non-common path aberrations (NCPAs) are a critical issue encountered when using an AO system to produce corrected images in an associated astronomical instrument. The AO wavefront sensor (WFS) and the supported scientific instrument typically use a series of different optical elements, thus experiencing different aberrations. The usual way to correct for such NCPAs is to introduce a static offset in the WFS signals. In this way, when the AO loop is closed the sensor offsets are zeroed and the deformable mirror converges to the shape required to null the NCPA. The method assumes that the WFS operation is linear and completely described by some pre-calibrated interaction matrix. This is not the case for some frequently used wavefront sensors like the Pyramid sensor or a quad-cell Shack-Hartmann sensor. Here we present a method to work in closed-loop with a pyramid wavefront sensor, or more generally a non-linear WFS, introducing a wavefront offset that remains stable when AO correction quality changes due to variations in external conditions like star brightness, seeing, and wind speed. The paper details the methods with analytical and numerical considerations. Then we present results of tests executed at the LBT telescope, in daytime and on sky, using the FLAO system and LUCI2 facility instrument. The on-sky results clearly show the successful operation of the method that completely nulls NCPA, recovering diffraction-limited images with about 70% Strehl ratio in H band in variable seeing conditions. The proposed method is suitable for application to the above-mentioned ELT AO systems.

APA, Harvard, Vancouver, ISO, and other styles

43

Wei, Xiang, Yuanyuan Wang, Zhan Cao, Dziki Mbemba, Azhar Iqbal, and Zhizheng Wu. "Large Aberration Correction by Magnetic Fluid Deformable Mirror with Model-Based Wavefront Sensorless Control Algorithm." International Journal of Molecular Sciences 20, no. 15 (July 28, 2019): 3697. http://dx.doi.org/10.3390/ijms20153697.

Full text

Abstract:

Magnetic fluid is a stable colloidal suspension of nano-sized, single-domain ferri/ferromagnetic particles dispersed in a liquid carrier. The liquid can be magnetized by the ferromagnetic particles aligned with the external magnetic field, which can be used as a wavefront corrector to correct the large aberrations up to more than 100 µm in adaptive optics (AO) systems. Since the measuring range of the wavefront sensor is normally small, the application of the magnetic fluid deformable mirror (MFDM) is limited with the WFS based AO system. In this paper, based on the MFDM model and the relationship between the second moment (SM) of the aberration gradients and the far-field intensity distribution, a model-based wavefront sensorless (WFSless) control algorithm is proposed for the MFDM. The correction performance of MFDM using the model-based control algorithm is evaluated in a WFSless AO system setup with a prototype MFDM, where a laser beam with unknown aberrations is supposed to produce a focused spot on the CCD. Experimental results show that the MFDM can be used to effectively compensate for unknown aberrations in the imaging system with the proposed model-based control algorithm.

APA, Harvard, Vancouver, ISO, and other styles

44

Li, Bo, Siyuan Yu, Jing Ma, and Liying Tan. "A Neural Network-Based Method for Fast Capture and Tracking of Laser Links between Nonorbiting Platforms." Computational Intelligence and Neuroscience 2022 (January 21, 2022): 1–11. http://dx.doi.org/10.1155/2022/9296770.

Full text

Abstract:

In this paper, a neural network approach is used to conduct an in-depth study and analysis of the fast capture tracking method for laser links between nonorbiting platforms. The experimental platform of the convolutional neural network- (CNN-) based free-space optical communication (FSO) wavefront correction system is built indoors, and the wavefront distortion correction performance of the CNN-based wavefront correction method is investigated. The experimental results show that the coupling power loss can be reduced to small after the CNN method correction under weak and strong turbulence. The accuracy of the above model is verified by comparing the simulation data with the experimentally measured data, thus realizing the coordinate decoupling of the coarse aiming mechanism and weakening the influence of structural factors on the tracking accuracy of the system. The tracking correlation equation of the influence of beam far-field dynamic characteristics on the tracking stability of the link is established, and the correlation factor variance of beam far-field dynamic characteristics is used to provide a quantitative analysis method for the evaluation and prediction of the comprehensive performance of the link tracking stability. The influence of beam divergence angle, wavefront distortion, detector accuracy, and atmospheric turbulence disturbance on the correlation factor variance of beam far-field dynamic characteristics of laser link beacons is modelled, and the link tracking stability optimization method is proposed under the requirement of link tracking accuracy, which provides an effective solution analysis method to realize the improvement of laser link tracking stability.

APA, Harvard, Vancouver, ISO, and other styles

45

Averich, V. V., and G. B. Egorova. "Ocular aberrations in keratoconus." Russian Journal of Clinical Ophthalmology 22, no. 3 (2022): 168–74. http://dx.doi.org/10.32364/2311-7729-2022-22-3-168-174.

Full text

Abstract:

The review presents the basic concepts of the wavefront, ocular aberrations and their changes in keratoconus (KC) — the most common form of primary ectatic corneal disorder. It also considers the issues of the posterior corneal surface impact on the indicators of general astigmatism and the wavefront. The authors note that a possible reason for the increase in the aberration level in KC are concomitant signs of dry eye syndrome (DYS). Adding that, the review also discusses methods for correcting aberrations in KC. To date, contact lens vision correction with rigid gas permeable lenses remains the most effective method of visual rehabilitation. The prescription with a combination of artificial tears and reparative medicine allows to almost completely neutralize the phenomena of keratomalacia (conjunctival xerosis). If a patient with KC has initial signs of DYS, it is advisable to use preservative-free low-viscosity artificial tears based on hyaluronic acid of various concentrations. If the patient uses contact lens vision correction to prevent hypoxia complications, it is justified to prescribe the antioxidant agent, methylethylpiridinol, which has an antiaggregational and antihypoxic effect. Keywords: keratoconus, ocular aberrations, posterior corneal surface, wavefront, Zernike polynomials, dry eye syndrome, antioxidant. For citation: Averich V.V., Egorova G.B. Ocular aberrations in keratoconus. Russian Journal of Clinical Ophthalmology. 2022;22(3):168– 174 (in Russ.). DOI: 10.32364/2311-7729-2022-22-3-168-174.

APA, Harvard, Vancouver, ISO, and other styles

46

Doga, A. V., I. A. Mushkova, A. N. Karimova, and A. N. Dzhaber. "Corneal wavefront-guided laser ablation in a patient with primary ametropia and no effect with subjective spherical-cylindrical correction." Russian ophthalmology of children, no. 3 (November 7, 2022): 58–63. http://dx.doi.org/10.25276/2307-6658-2022-3-58-63.

Full text

Abstract:

Purpose. To evaluate the clinical and functional results of FemtoLASIK surgery using a corneal wavefront-guided laser ablation algorithm in a patient with primary ametropia and no effect with subjective spherical-cylindrical correction. Material and methods. Patient N., 26 years old, diagnosed with amblyopia of both eyes. The visual acuity of the right eye was 0.3 n/c, the left eye 0.2 n/c. The patient had no possibility of subjective spherical-cylindrical correction. FemtoLASIK surgery was performed using a personalized laser ablation algorithm based on keratotopography data. Results. A month after the operation, visual acuity increased and amounted to 0.6 of the right eye and 0.5 of the left eye, the patient had the opportunity for subjective correction, the best corrected visual acuity of 0.9 of each eye was determined. A year after the operation, the residual cylindrical component was corrected. After the second stage of the treatment, uncorrected visual acuity was 1.0 in the right and 0.9 in the left eyes. Conclusions. The presented clinical case demonstrates the successful result of using a corneal wavefront-guided laser ablation algorithm in a patient with primary ametropia and no effect with subjective spherical-cylindrical correction. Key words: Corneal wavefront; excimer laser ablation, astigmatism; FemtoLASIK

APA, Harvard, Vancouver, ISO, and other styles

47

Tian, Li Feng, Shi He Yi, Yang Zhu Zhu, Yu Xin Zhao, and Lin He. "Aero-Optical Effects of Mc=0.5 Supersonic Mixing Layer." Advanced Materials Research 989-994 (July 2014): 863–66. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.863.

Full text

Abstract:

Supersonic turbulent mixing layer requires high spatiotemporal resolution of measuring techniques to study its aero-optical effects. However, the spatiotemporal resolution of existing techniques is not high enough. NPLS-WT (NPLS based wavefront technique) is a new aero-optics measuring technique developed in 2010. Its time resolution is 6ns, and spatial resolution and time correction resolution can reach up to micrometers and 200ns respectively. NPLS-WT was used in this paper to study aero-optical effects induced by Mc=0.5 supersonic mixing layer. The fine wavefront aberration information is revealed by the OPD of high resolution. The results show that the wavefront in near field is not sensitive to the resolution, and large-scale structures play a dominant role on the wavefront in near field. The cumulative effects analysis show us that the density difference between large-scale structures and free stream is the main reason to wavefront aberration, and the larger the vortex is, the more obvious the effect to wavefront aberration is.

APA, Harvard, Vancouver, ISO, and other styles

48

Samarkin, V. V., A. G. Alexandrov, I. V. Galaktionov, A. V. Kudryashov, A. N. Nikitin, A. L. Rukosuev, V. V. Toporovsky, and Yu V. Sheldakova. "Large-aperture adaptive optical system for correcting wavefront distortions of a petawatt Ti : sapphire laser beam." Quantum Electronics 52, no. 2 (February 1, 2022): 187–94. http://dx.doi.org/10.1070/qel17989.

Full text

Abstract:

Abstract This paper reports a large-aperture adaptive optical system with a bimorph deformable mirror and Shack – Hartmann wavefront sensor for aberration correction and beam focusing improvement in state-of-the-art petawatt Ti : sapphire lasers. We consider methods for providing feedback to the wavefront sensor and obtaining an objective wavefront that optimises beam focusing onto a target. The use of an adaptive system with a controlled 127-channel 320-mm-aperture mirror in a Ti : sapphire laser with an output power of 4.2 PW has made it possible to obtain a record high laser beam intensity: 1.1 × 1023 W cm−2.

APA, Harvard, Vancouver, ISO, and other styles

49

Chambouleyron, V., O. Fauvarque, P. Janin-Potiron, C. Correia, J.-F. Sauvage, N. Schwartz, B. Neichel, and T. Fusco. "Pyramid wavefront sensor optical gains compensation using a convolutional model." Astronomy & Astrophysics 644 (November 24, 2020): A6. http://dx.doi.org/10.1051/0004-6361/202037836.

Full text

Abstract:

Context. Extremely large telescopes are overwhelmingly equipped with pyramid wavefront sensors (PyWFS) over the more widely used Shack–Hartmann wavefront sensor to perform their single-conjugate adaptive optics (SCAO) mode. The PyWFS, a sensor based on Fourier filtering, has proven to be highly successful in many astronomy applications. However, this sensor exhibits non-linear behaviours that lead to a reduction of the sensitivity of the instrument when working with non-zero residual wavefronts. This so-called optical gains (OG) effect, degrades the closed-loop performance of SCAO systems and prevents accurate correction of non-common path aberrations (NCPA). Aims. In this paper, we aim to compute the OG using a fast and agile strategy to control PyWFS measurements in adaptive optics closed-loop systems. Methods. Using a novel theoretical description of PyWFS, which is based on a convolutional model, we are able to analytically predict the behaviour of the PyWFS in closed-loop operation. This model enables us to explore the impact of residual wavefront errors on particular aspects such as sensitivity and associated OG. The proposed method relies on the knowledge of the residual wavefront statistics and enables automatic estimation of the current OG. End-to-end numerical simulations are used to validate our predictions and test the relevance of our approach. Results. We demonstrate, using on non-invasive strategy, that our method provides an accurate estimation of the OG. The model itself only requires adaptive optics telemetry data to derive statistical information on atmospheric turbulence. Furthermore, we show that by only using an estimation of the current Fried parameter r0 and the basic system-level characteristics, OGs can be estimated with an accuracy of less than 10%. Finally, we highlight the importance of OG estimation in the case of NCPA compensation. The proposed method is applied to the PyWFS. However, it remains valid for any wavefront sensor based on Fourier filtering subject from OG variations.

APA, Harvard, Vancouver, ISO, and other styles

50

C. S. IH, WANG YONG-ZHAO, WU JI-ZONG, and XIANG LIAN-QIN. "COMPUTER-GENERATED HOLOGRAM FOR ELLIPTICAL GAUSSIAN WAVEFRONT CORRECTION." Acta Physica Sinica 35, no. 2 (1986): 220. http://dx.doi.org/10.7498/aps.35.220.

Full text

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!