Journal articles: 'Ultrafast Laser pulses'

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Wei, Xianqi, Xiaoli Wang, Xin Li, and Weihua Liu. "Electronic Pulses from Pulsed Field Emission of CNT Cathodes." Journal of Nanomaterials 2018 (2018): 1–6. http://dx.doi.org/10.1155/2018/4396430.

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We presented a demonstration of infrared laser irradiated field emission electronic pulse based on carbon nanotube (CNT) cathodes. Electronic pulses greatly depended on pulsed infrared laser and were almost synchronous with laser pulses. We have designed a pulsed field emission cathode based on CNTs and investigated correlation between electronic pulse and laser pulse, acquiring the shortest width of electronic pulses about 50 ms and turn-on field less than 0.14 V/μm. Besides, we have studied the thermal effect on the pulsed field emission of CNT cathodes caused by laser heating. Interestingly, the thermal effect has caused an enhancement of emission current but resulted in a waveform distortion on short electronic pulses. The application of laser pulses on CNT cathodes would extend conventional electron sources to a pulsed electron source and offered a possibility of pulsed field emission. These results were encouraging us to prepare further studies of ultrafast electronic pulses for high-frequency electron sources.

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Wang, Hongjie, Dmitry Gaponov, Amélie Cabasse, Gilles Martel, Ammar Hideur, Jean-Louis Oudar, Leonid Kotov, Mikhail Likhachev, Denis Lipatov, and Sébastien Février. "1.55-μm wavelength ultrafast fiber oscillators and amplifiers." International Journal of Modern Physics B 28, no. 12 (April 7, 2014): 1442004. http://dx.doi.org/10.1142/s0217979214420041.

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In this paper, we review our recent developments on ultrafast pulse generation in erbium-doped fiber laser systems operating in the 1550 nm wavelength range. This work concerns the generation of ultrafast pulses from dissipative soliton fiber lasers featuring resonant saturable absorber mirrors, as well as their amplification in highly efficient erbium-doped large-mode-area fibers. Different amplification schemes featuring all-fiber components are studied leading to the achievement of record pulse energy from a high repetition rate laser system.

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Viana, Bruno, J. Petit, R. Gaumé, Philippe Goldner, F. Druon, F. Balembois, and P. Georges. "Crystal Chemistry Approach in Yb Doped Laser Materials." Materials Science Forum 494 (September 2005): 259–64. http://dx.doi.org/10.4028/www.scientific.net/msf.494.259.

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The emergence of new laser crystals has allowed progress in ultrashort-pulsed laser technology and high power lasers. Extensive researches on new Yb3+ doped crystals enable development of all-solid-state femtosecond lasers. Thermo-mechanical properties should be taken into account. The review of the state of the art on the Yb doped laser material for high power and ultrafast pulses generation is presented.

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Taft, Gregory J., Matthew T. Newby, Joel J. Hrebik, Marshall Onellion, Thomas F. George, Dániel Szentesi, Sándor Szatmári, and László Nánai. "Ultrafast dynamic reflectivity of vanadium pentoxide." Journal of Materials Research 23, no. 2 (February 2008): 308–11. http://dx.doi.org/10.1557/jmr.2008.0039.

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The ultrafast dynamic reflectivity of vanadium pentoxide is measured using 40 fs pulses from a self-mode-locked Ti:sapphire laser. The laser pulses excite acoustic vibrations at wave numbers of 145 and 103 cm−1. The amplitudes of the induced oscillations depend strongly on the orientation between the linear polarization of the laser pulses and the crystal axes, with the largest oscillations observed for an orientation of 45°. The higher-frequency oscillation is induced immediately upon arrival of the laser pulse, while the lower-frequency oscillation appears a few picoseconds later. The oscillations persist for approximately 10 ps after the arrival of the pulse. The oscillations are attributed to transverse acoustic modes propagating along the a-axis of the crystal.

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Sugioka, Koji. "Progress in ultrafast laser processing and future prospects." Nanophotonics 6, no. 2 (March 1, 2017): 393–413. http://dx.doi.org/10.1515/nanoph-2016-0004.

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AbstractThe unique characteristics of ultrafast lasers have rapidly revolutionized materials processing after their first demonstration in 1987. The ultrashort pulse width of the laser suppresses heat diffusion to the surroundings of the processed region, which minimizes the formation of a heat-affected zone and thereby enables ultrahigh precision micro- and nanofabrication of various materials. In addition, the extremely high peak intensity can induce nonlinear multiphoton absorption, which extends the diversity of materials that can be processed to transparent materials such as glass. Nonlinear multiphoton absorption enables three-dimensional (3D) micro- and nanofabrication by irradiation with tightly focused femtosecond laser pulses inside transparent materials. Thus, ultrafast lasers are currently widely used for both fundamental research and practical applications. This review presents progress in ultrafast laser processing, including micromachining, surface micro- and nanostructuring, nanoablation, and 3D and volume processing. Advanced technologies that promise to enhance the performance of ultrafast laser processing, such as hybrid additive and subtractive processing, and shaped beam processing are discussed. Commercial and industrial applications of ultrafast laser processing are also introduced. Finally, future prospects of the technology are given with a summary.

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Sotor, Jaroslaw, and Grzegorz Sobon. "Ultrafast lasers and their applications." Photonics Letters of Poland 8, no. 4 (December 31, 2016): 94. http://dx.doi.org/10.4302/plp.2016.4.01.

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The editors introduce the special issue on "Ultrafast lasers and their applications". It covers topics from ultrashort laser pulses generation using nanomaterials-based saturable absorbers to practical applications of such lasers in spectroscopy, supercontinuum generation and laser micromachining. The issue contains nine papers tightly focused on the main topic and two regular papers.

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Fan, C. H., J. Sun, and J. P. Longtin. "Plasma Absorption of Femtosecond Laser Pulses in Dielectrics." Journal of Heat Transfer 124, no. 2 (October 22, 2001): 275–83. http://dx.doi.org/10.1115/1.1445135.

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Dielectric (high bandgap) materials represent an important and diverse class of materials in micro and nanotechnology, including MEMS devices, biomedical and bioengineering systems, multilayer thin film coatings, fiber optics, etc. Micromachining dielectrics using ultrafast lasers is an exciting and promising new research area with many significant advantages, including precision material removal, negligible heating of the workpiece, micron and sub-micron-size feature fabrication, and high aspect ratio features. During ultrafast laser processing of dielectrics, the intense laser pulse ionizes the irradiated material and produces an optical breakdown region, or plasma, that is characterized by a high density of free electrons. These high-density electrons can efficiently absorb a large fraction of the laser irradiance energy, part of which will then be coupled into the bulk material, resulting in material removal through direct vaporization. The energy deposited into the material depends on the time and space-dependent breakdown region, the plasma rise time, and the plasma absorption coefficient. Higher coupling efficiency results in higher material removal rate; thus energy deposition is one of the most important issues for ultrafast laser materials processing, particularly for micron and sub-micron-scale laser materials processing. In the present work, a femtosecond breakdown model is developed to investigate energy deposition during ultrafast laser material interactions. One substantial contribution of the current work is that pulse propagation effects have been taken into account, which have been shown to become significant for pulse durations less than 10 ps. By accounting for the pulse propagation, the time and space-resolved plasma evolution can be characterized and used to determine the energy deposition through plasma absorption. With knowledge of the plasma absorption, changes in the pulse profile as it propagates in the focal region can be determined as well. Absorption of the laser pulse by plasma in water is compared with experimental data to validate the model, as water is a well characterized dielectric. The model, however, is also applicable to other transparent or moderately absorbing solid and liquid dielectric media during ultrafast laser-materials interactions.

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Ren, Zhong, and Xiaojing Yang. "Angular-split/temporal-delay approach to ultrafast protein dynamics at XFELs." Acta Crystallographica Section D Structural Biology 72, no. 7 (June 23, 2016): 871–82. http://dx.doi.org/10.1107/s2059798316008573.

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X-ray crystallography promises direct insights into electron-density changes that lead to and arise from structural changes such as electron and proton transfer and the formation, rupture and isomerization of chemical bonds. The ultrashort pulses of hard X-rays produced by free-electron lasers present an exciting opportunity for capturing ultrafast structural events in biological macromolecules within femtoseconds after photoexcitation. However, shot-to-shot fluctuations, which are inherent to the very process of self-amplified spontaneous emission (SASE) that generates the ultrashort X-ray pulses, are a major source of noise that may conceal signals from structural changes. Here, a new approach is proposed to angularly split a single SASE pulse and to produce a temporal delay of picoseconds between the split pulses. These split pulses will allow the probing of two distinct states before and after photoexcitation triggered by a laser pulse between the split X-ray pulses. The split pulses originate from a single SASE pulse and share many common properties; thus, noise arising from shot-to-shot fluctuations is self-canceling. The unambiguous interpretation of ultrafast structural changes would require diffraction data at atomic resolution, as these changes may or may not involve any atomic displacement. This approach, in combination with the strategy of serial crystallography, offers a solution to study ultrafast dynamics of light-initiated biochemical reactions or biological processes at atomic resolution.

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Edziah, Raymond. "Cost Effective Profiling of Neodymium-Doped Vanadate Laser Pulses." Applied Physics Research 10, no. 2 (March 31, 2018): 39. http://dx.doi.org/10.5539/apr.v10n2p39.

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As environmental conditions and component degradation and failure are known to affect the performance of ultrafast lasers, it is important to monitor their state in any nonlinear optical study. This may be achieved by measuring the temporal width of the laser pulses using an autocorrelator. In this work, an autocorrelator for measuring the pulsewidth of mode-locked lasers was custom-built using pieces of equipment usually found in a typical ultrafast optics laboratory. The assembled equipment was tested using SESAM (Saturable Semiconductor Absorber Mirror) mode-locked neodymium-doped vanadate (Nd:YVO4) laser having manufacturer specified average output power of 1.6 W and 10 ps pulsewidth. Using the background-free autocorrelation technique, the pulse width of the laser was measured to be 10.4 ps. This type of autocorrelator is cost effective and may be handy in situations where research funds are limited; a scenario commonly experienced in research laboratories of developing countries. Additionally, the processes involved in assembling the autocorrelator provide a useful learning experience for new researchers. The study also outlined the processes involved in modifying an existing autocorrelation setup in order to measure laser beam spot size; a useful parameter in nonlinear optical studies.

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Garasz, Katarzyna, and Marek Kocik. "Experimental Investigations on Laser Ablation of Aluminum in Sub-Picosecond Regimes." Applied Sciences 10, no. 24 (December 12, 2020): 8883. http://dx.doi.org/10.3390/app10248883.

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Due to high power and ultrashort pulses, femtosecond lasers excel at (but are not limited to) processing materials whose thicknesses are less than 500 microns. Numerous experiments and theoretical analyses testify to the fact that there are solid grounds for the applications of ultrafast laser micromachining. However, with high costs and complexity of these devices, a sub-picosecond laser that might be an alternative when it comes to various micromachining applications, such as patterns and masks in thin metal foils, micro-nozzles, thermo-detectors, MEMS (micro electro-mechanical systems), sensors, etc. Furthermore, the investigation of sub-picosecond laser interactions with matter could provide more knowledge on the ablation mechanisms and experimental verification of existing models for ultrashort pulse regimes. In this article, we present the research on sub-picosecond laser interactions with thin aluminum foil under various laser pulse parameters. Research was conducted with two types of ultrafast lasers: a prototype sub-picosecond Yb:KYW laser (650 fs) and a commercially available femtosecond Ti:S laser (35 fs). The results show how the variables such as pulse width, energy, frequency, wavelength and irradiation time affect the micromachining process.

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Fu, Xuewen, Erdong Wang, Yubin Zhao, Ao Liu, Eric Montgomery, Vikrant J. Gokhale, Jason J. Gorman, Chunguang Jing, June W. Lau, and Yimei Zhu. "Direct visualization of electromagnetic wave dynamics by laser-free ultrafast electron microscopy." Science Advances 6, no. 40 (October 2020): eabc3456. http://dx.doi.org/10.1126/sciadv.abc3456.

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Integrating femtosecond lasers with electron microscopies has enabled direct imaging of transient structures and morphologies of materials in real time and space. Here, we report the development of a laser-free ultrafast electron microscopy (UEM) offering the same capability but without requiring femtosecond lasers and intricate instrumental modifications. We create picosecond electron pulses for probing dynamic events by chopping a continuous beam with a radio frequency (RF)–driven pulser with the pulse repetition rate tunable from 100 MHz to 12 GHz. As a first application, we studied gigahertz electromagnetic wave propagation dynamics in an interdigitated comb structure. We reveal, on nanometer space and picosecond time scales, the transient oscillating electromagnetic field around the tines of the combs with time-resolved polarization, amplitude, and local field enhancement. This study demonstrates the feasibility of laser-free UEM in real-space visualization of dynamics for many research fields, especially the electrodynamics in devices associated with information processing technology.

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Liu, Jiansheng, Hartmut Schroeder, See Leang Chin, Ruxin Li, and Zhizhan Xu. "Ultrafast control of multiple filamentation by ultrafast laser pulses." Applied Physics Letters 87, no. 16 (October 17, 2005): 161105. http://dx.doi.org/10.1063/1.2106022.

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Fadhel, Mahmoud Muhanad, Norazida Ali, Haroon Rashid, Nurfarhana Mohamad Sapiee, Abdulwahhab Essa Hamzah, Mohd Saiful Dzulkefly Zan, Norazreen Abd Aziz, and Norhana Arsad. "A Review on Rhenium Disulfide: Synthesis Approaches, Optical Properties, and Applications in Pulsed Lasers." Nanomaterials 11, no. 9 (September 12, 2021): 2367. http://dx.doi.org/10.3390/nano11092367.

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Rhenium Disulfide (ReS2) has evolved as a novel 2D transition-metal dichalcogenide (TMD) material which has promising applications in optoelectronics and photonics because of its distinctive anisotropic optical properties. Saturable absorption property of ReS2 has been utilized to fabricate saturable absorber (SA) devices to generate short pulses in lasers systems. The results were outstanding, including high-repetition-rate pulses, large modulation depth, multi-wavelength pulses, broadband operation and low saturation intensity. In this review, we emphasize on formulating SAs based on ReS2 to produce pulsed lasers in the visible, near-infrared and mid-infrared wavelength regions with pulse durations down to femtosecond using mode-locking or Q-switching technique. We outline ReS2 synthesis techniques and integration platforms concerning solid-state and fiber-type lasers. We discuss the laser performance based on SAs attributes. Lastly, we draw conclusions and discuss challenges and future directions that will help to advance the domain of ultrafast photonic technology.

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Wheeler, Jonathan, Gérard Mourou, and Toshiki Tajima. "Laser Technology for Advanced Acceleration: Accelerating Beyond TeV." Reviews of Accelerator Science and Technology 09 (January 2016): 151–63. http://dx.doi.org/10.1142/s1793626816300073.

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The implementation of the suggestion of thin film compression (TFC) allows the newest class of high power, ultrafast laser pulses (typically 20[Formula: see text]fs at near-infrared wavelengths) to be compressed to the limit of a single-cycle laser pulse (2[Formula: see text]fs). Its simplicity and high efficiency, as well as its accessibility to a single-cycle laser pulse, introduce a new regime of laser–plasma interaction that enhances laser acceleration. Single-cycle laser acceleration of ions is a far more efficient and coherent process than the known laser-ion acceleration mechanisms. The TFC-derived single-cycle optical pulse is capable of inducing a single-cycle X-ray laser pulse (with a far shorter pulse length and thus an extremely high intensity) through relativistic compression. The application of such an X-ray pulse leads to the novel regime of laser wakefield acceleration of electrons in the X-ray regime, yielding a prospect of “TeV on a chip.” This possibility of single-cycle X-ray pulses heralds zeptosecond and EW lasers (and zeptoscience). The additional invention of the coherent amplification network (CAN) fiber laser pushes the frontier of high repetition, high efficiency lasers, which are the hallmark of needed applications such as laser-driven LWFA colliders and other, societal applications. CAN addresses the crucial aspect of intense lasers that have traditionally lacked the above properties.

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Carlson, David R., Daniel D. Hickstein, Wei Zhang, Andrew J. Metcalf, Franklyn Quinlan, Scott A. Diddams, and Scott B. Papp. "Ultrafast electro-optic light with subcycle control." Science 361, no. 6409 (September 27, 2018): 1358–63. http://dx.doi.org/10.1126/science.aat6451.

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Light sources that are ultrafast and ultrastable enable applications like timing with subfemtosecond precision and control of quantum and classical systems. Mode-locked lasers have often given access to this regime, by using their high pulse energies. We demonstrate an adaptable method for ultrastable control of low-energy femtosecond pulses based on common electro-optic modulation of a continuous-wave laser light source. We show that we can obtain 100-picojoule pulse trains at rates up to 30 gigahertz and demonstrate sub–optical cycle timing precision and useful output spectra spanning the near infrared. Our source enters the few-cycle ultrafast regime without mode locking, and its high speed provides access to nonlinear measurements and rapid transients.

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Debnath, Pulak Chandra, and Dong-Il Yeom. "Ultrafast Fiber Lasers with Low-Dimensional Saturable Absorbers: Status and Prospects." Sensors 21, no. 11 (May 25, 2021): 3676. http://dx.doi.org/10.3390/s21113676.

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Wide-spectral saturable absorption (SA) in low-dimensional (LD) nanomaterials such as zero-, one-, and two-dimensional materials has been proven experimentally with outstanding results, including low saturation intensity, deep modulation depth, and fast carrier recovery time. LD nanomaterials can therefore be used as SAs for mode-locking or Q-switching to generate ultrafast fiber laser pulses with a high repetition rate and short duration in the visible, near-infrared, and mid-infrared wavelength regions. Here, we review the recent development of emerging LD nanomaterials as SAs for ultrafast mode-locked fiber laser applications in different dispersion regimes such as anomalous and normal dispersion regimes of the laser cavity operating in the near-infrared region, especially at ~1550 nm. The preparation methods, nonlinear optical properties of LD SAs, and various integration schemes for incorporating LD SAs into fiber laser systems are introduced. In addition to these, externally (electrically or optically) controlled pulsed fiber laser behavior and other characteristics of various LD SAs are summarized. Finally, the perspectives and challenges facing LD SA-based mode-locked ultrafast fiber lasers are highlighted.

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Zhang, Feijuan, Wenyan Yan, Shengnan Liang, Chao Tan, and Pinghua Tang. "Numerical Study on the Soliton Mode-Locking of the Er3+-Doped Fluoride Fiber Laser at ~3 μm with Nonlinear Polarization Rotation." Photonics 6, no. 1 (March 6, 2019): 25. http://dx.doi.org/10.3390/photonics6010025.

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Recent interest in the application of mid-infrared (mid-IR) lasers has made the generation of ~3 µm ultrafast pulses a hot topic. Recently, the generation of femtosecond-scale pulses in Er3+-doped fluoride fiber lasers has been realized by nonlinear polarization rotation (NPR). However, a numerical study on these fiber lasers has not been reported yet. In this work, the output properties of the NPR passively mode-locked Er3+-doped fluoride fiber ring laser in ~3 µm have been numerically investigated based on the coupled Ginzburg–Landu equation. The simulation results indicate that stable uniform solitons (0.75 nJ) with the pulse duration of femtosecond-scale can be generated from this fiber laser. This numerical investigation can provide some reference for developing the high energy femtosecond soliton fiber lasers in the mid-IR.

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Tehrani, P. H., L. G. Hector,, R. B. Hetnarski, and M. R. Eslami. "Boundary Element Formulation for Thermal Stresses During Pulsed Laser Heating." Journal of Applied Mechanics 68, no. 3 (December 5, 2000): 480–89. http://dx.doi.org/10.1115/1.1365155.

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Pulsed lasers are used in a variety of materials processing applications that range from heating for metallurgical transformation to scribing vehicle identification numbers on anodized aluminum strips. These lasers are commonly configured to deliver a large quantity of heat energy in very short time intervals and over very small areas due to the manner in which radiant energy is stored within, and then released from, the laser resonator. At the present time, little is known about the effect of pulse duration on thermomechanical distortion during heating without phase change. To explore this issue, a boundary element method was developed to calculate temperature, displacement, and thermal stress fields in a layer that is rigidly bonded to an inert semi-space. The layer absorbs thermal energy from a repetitively pulsed laser in the plane of its free surface. The effects of two pulse durations, which differ by four-orders-of-magnitude, were examined in this work. The temporal profiles of ultrafast pulses of the order of ten picoseconds (such as those emitted by a mode-locked laser), and pulses of the order of tens-of-nanoseconds (such as those emitted by a Q-switched Nd:YAG laser) were mathematically modeled using a rectified sine function. The spatial profile of each pulse was shaped to approximate a Gaussian strip source. The equations of coupled thermoelasticity, wherein the speed of mechanical distortion due to material expansion during heat absorption is finite, but the speed of heat propagation within the layer is infinite, were solved for both pulse durations. The resulting temperature and stress fields were compared with those predicted in the limit of no thermomechanical coupling.

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Holzwarth, Alfred R. "Applications of ultrafast laser spectroscopy for the study of biological systems." Quarterly Reviews of Biophysics 22, no. 3 (August 1989): 239–326. http://dx.doi.org/10.1017/s0033583500002985.

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The discovery of mode-locked laser operation now nearly two decades ago has started a development which enables researchers to probe the dynamics of ultrafast physical and chemical processes at the molecular level on shorter and shorter time scales. Naturally the first applications were in the fields of photophysics and photochemistry where it was then possible for the first time to probe electronic and vibrational relaxation processes on a sub-nanosecond timescale. The development went from lasers producing pulses of many picoseconds to the shortest pulses which are at present just a few femtoseconds long. Soon after their discovery ultrashort pulses were applied also to biological systems which has revealed a wealth of information contributing to our understanding of a broadrange of biological processes on the molecular level.It is the aim of this review to discuss the recent advances and point out some future trends in the study of ultrafast processes in biological systems using laser techniques. The emphasis will be mainly on new results obtained during the last 5 or 6 years. The term ultrafast means that I shall restrict myself to sub-nanosecond processes with a few exceptions.

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Berger, Joel A., John T. Hogan, Michael J. Greco, W. Andreas Schroeder, Alan W. Nicholls, and Nigel D. Browning. "DC Photoelectron Gun Parameters for Ultrafast Electron Microscopy." Microscopy and Microanalysis 15, no. 4 (July 3, 2009): 298–313. http://dx.doi.org/10.1017/s1431927609090266.

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AbstractWe present a characterization of the performance of an ultrashort laser pulse driven DC photoelectron gun based on the thermionic emission gun design of Togawa et al. [Togawa, K., Shintake, T., Inagaki, T., Onoe, K. & Tanaka, T. (2007). Phys Rev Spec Top-AC10, 020703]. The gun design intrinsically provides adequate optical access and accommodates the generation of ∼1 mm2 electron beams while contributing negligible divergent effects at the anode aperture. Both single-photon (with up to 20,000 electrons/pulse) and two-photon photoemission are observed from Ta and Cu(100) photocathodes driven by the harmonics (∼4 ps pulses at 261 nm and ∼200 fs pulses at 532 nm, respectively) of a high-power femtosecond Yb:KGW laser. The results, including the dependence of the photoemission efficiency on the polarization state of the drive laser radiation, are consistent with expectations. The implications of these observations and other physical limitations for the development of a dynamic transmission electron microscope with sub-1 nm·ps space-time resolution are discussed.

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Coffee, Ryan N., James P. Cryan, Joseph Duris, Wolfram Helml, Siqi Li, and Agostino Marinelli. "Development of ultrafast capabilities for X-ray free-electron lasers at the linac coherent light source." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377, no. 2145 (April 2019): 20180386. http://dx.doi.org/10.1098/rsta.2018.0386.

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The ability to produce ultrashort, high-brightness X-ray pulses is revolutionizing the field of ultrafast X-ray spectroscopy. Free-electron laser (FEL) facilities are driving this revolution, but unique aspects of the FEL process make the required characterization and use of the pulses challenging. In this paper, we describe a number of developments in the generation of ultrashort X-ray FEL pulses, and the concomitant progress in the experimental capabilities necessary for their characterization and use at the Linac Coherent Light Source. This includes the development of sub-femtosecond hard and soft X-ray pulses, along with ultrafast characterization techniques for these pulses. We also describe improved techniques for optical cross-correlation as needed to address the persistent challenge of external optical laser synchronization with these ultrashort X-ray pulses. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

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Liu, Ji-Shu, Xiao-Hui Li, Abdul Qyyum, Yi-Xuan Guo, Tong Chai, Hua Xu, and Jie Jiang. "Fe3O4 nanoparticles as a saturable absorber for giant chirped pulse generation." Beilstein Journal of Nanotechnology 10 (May 20, 2019): 1065–72. http://dx.doi.org/10.3762/bjnano.10.107.

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Fe3O4 nanoparticles (FONPs) are magnetic materials with a small band gap and have well-demonstrated applications in ultrafast photonics, medical science, magnetic detection, and electronics. Very recently, FONPs were proposed as an ideal candidate for pulse generation in fiber-based oscillators. However, the pulses obtained to date are on the order of microseconds, which is too long for real application in communication. Here, we report the use of FONPs synthesized by a sol–hydrothermal method and used as a saturable absorber (SA) to achieve nanosecond pulses in an erbium-doped fiber laser (EDFL) for the first time. The proposed fiber laser is demonstrated to have a narrow spectral width of around 0.8 nm and a fixed fundamental repetition rate (RPR) of 4.63 MHz, whose spectra and pulse dynamics are different from the mode-locked lasers reported previously. It is demonstrated that the proposed fiber laser based on a FONP SA operates in the giant-chirp mode-locked regime. The most important result is the demonstration of a pulse duration of 55 ns at an output power of 16.2 mW, which is the shortest pulse based on FONPs for EDFLs reported to date. Our results demonstrate that the FONP dispersion allows for an excellent photonic material for application in ultrafast photonics devices, photoconductive detectors, and optical modulators.

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Liu, Shande, Yuqing Zhao, Ke Zhang, Bo Chen, Ning Zhang, Dehua Li, Huiyun Zhang, et al. "Tunable and Passively Mode-Locking Nd0.01:Gd0.89La0.1NbO4 Picosecond Laser." Molecules 26, no. 11 (May 26, 2021): 3179. http://dx.doi.org/10.3390/molecules26113179.

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A high-quality Nd0.01:Gd0.89La0.1NbO4 (Nd:GLNO) crystal is grown by the Czochralski method, demonstrating wide absorption and fluorescence spectra and advantage for producing ultrafast laser pulses. In this paper, the tunable and passively mode-locking Nd:GLNO lasers are characterized for the first time. The tuning coverage is 34.87 nm ranging from 1058.05 to 1092.92 nm with a maximum output power of 4.6 W at 1065.29 nm. A stable continuous-wave (CW) passively mode-locking Nd:GLNO laser is achieved at 1065.26 nm, delivering a pulse width of 9.1 ps and a maximum CW mode-locking output power of 0.27 W.

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Gu, Chenglin, Dapeng Zhang, Yina Chang, and Shih-Chi Chen. "Arbitrary amplitude femtosecond pulse shaping via a digital micromirror device." Journal of Innovative Optical Health Sciences 12, no. 01 (January 2019): 1840002. http://dx.doi.org/10.1142/s1793545818400023.

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An ultrafast spectrum programmable femtosecond laser may enhance the performance of a wide variety of scientific applications, e.g., multi-photon imaging. In this paper, we report a digital micromirror device (DMD)-based ultrafast pulse shaper, i.e., DUPS, for femtosecond laser arbitrary amplitude shaping — the first time a programmable binary device reported to shape the amplitudes of ultrafast pulses spectrum at up to 32[Formula: see text]kHz rate over a broad wavelength range. The DUPS is highly efficient, compact, and low cost based on the use of a DMD in combination with a transmission grating. Spatial and temporal dispersion introduced by the DUPS is compensated by a quasi-4-f setup and a grating pair, respectively. Femtosecond pulses with arbitrary spectrum shapes, including rectangular, sawtooth, triangular, double-pulse, and exponential profile, have been demonstrated in our experiments. A feedback operation process is implemented in the DUPS to ensure a robust and repeatable shaping process. The total efficiency of the DUPS for amplitude shaping is measured to be 27%.

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Mauclair, Cyril. "Multipoint Focusing of Single Ultrafast Laser Pulses." Journal of Laser Micro/Nanoengineering 6, no. 3 (December 2011): 239–44. http://dx.doi.org/10.2961/jlmn.2011.03.0013.

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Hiromatsu, K., D. J. Hwang, and C. P. Grigoropoulos. "Active glass nanoparticles by ultrafast laser pulses." Micro & Nano Letters 3, no. 4 (2008): 121. http://dx.doi.org/10.1049/mnl:20080028.

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Schmidt, Timothy W., Thomas Feurer, Rodrigo B. López-Martens, and Gareth Roberts. "ac-Stark autocorrelator for ultrafast laser pulses." Journal of the Optical Society of America B 19, no. 8 (August 1, 2002): 1930. http://dx.doi.org/10.1364/josab.19.001930.

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Palmer, Guido, Martin Kellert, Jinxiong Wang, Moritz Emons, Ulrike Wegner, Daniel Kane, Florent Pallas, et al. "Pump–probe laser system at the FXE and SPB/SFX instruments of the European X-ray Free-Electron Laser Facility." Journal of Synchrotron Radiation 26, no. 2 (February 15, 2019): 328–32. http://dx.doi.org/10.1107/s160057751900095x.

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User operation at the European X-ray Free-Electron Laser Facility started at the SASE1 undulator beamline in fall 2017. The majority of the experiments utilize optical lasers (mostly ultrafast) for pump–probe-type measurements in combination with X-ray pulses. This manuscript describes the purpose-developed pump–probe laser system as installed at SASE1, implemented features and plans for further upgrades.

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Wang, Andong, Amlan Das, and David Grojo. "Ultrafast Laser Writing Deep inside Silicon with THz-Repetition-Rate Trains of Pulses." Research 2020 (May 14, 2020): 1–11. http://dx.doi.org/10.34133/2020/8149764.

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Three-dimensional laser writing inside silicon remains today inaccessible with the shortest infrared light pulses unless complex schemes are used to circumvent screening propagation nonlinearities. Here, we explore a new approach irradiating silicon with trains of femtosecond laser pulses at repetition rates up to 5.6 THz that is order of magnitude higher than any source used for laser processing so far. This extremely high repetition rate is faster than laser energy dissipation from microvolume inside silicon, thus enabling unique capabilities for pulse-to-pulse accumulation of free carriers generated by nonlinear ionization, as well as progressive thermal bandgap closure before any diffusion process comes into play. By space-resolved measurements of energy delivery inside silicon, we evidence changes in the interplay between detrimental nonlinearities and accumulation-based effects. This leads to a net increase on the level of space-time energy localization. The improvement is also supported by experiments demonstrating high performance for 3D laser writing inside silicon. In comparison to repeated single pulses, irradiation with trains of only four-picosecond pulses with the same total energy leads to an apparent decrease of the energy threshold for modification and drastic improvements on the repeatability, uniformity, and symmetricity of the produced features. The unique benefits of THz bursts can provide a new route to meet the challenge of 3D inscription inside narrow bandgap materials.

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Farinella, D. M., M. Stanfield, N. Beier, T. Nguyen, S. Hakimi, T. Tajima, F. Dollar, J. Wheeler, and G. Mourou. "Demonstration of thin film compression for short-pulse X-ray generation." International Journal of Modern Physics A 34, no. 34 (December 10, 2019): 1943015. http://dx.doi.org/10.1142/s0217751x19430152.

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Thin film compression to the single-cycle regime combined with relativistic compression offers a method to transform conventional ultrafast laser pulses into attosecond X-ray laser pulses. These attosecond X-ray laser pulses are required to drive wakefields in solid density materials which can provide acceleration gradients of up to TeV/cm. Here we demonstrate a nearly 99% energy efficient compression of a 6.63 mJ, 39 fs laser pulse with a Gaussian mode to 20 fs in a single stage. Further, it is shown that as a result of Kerr-lensing, the focal spot of the system is slightly shifted on-axis and can be recovered by translating the imaging system to the new focal plane. This implies that with the help of wave-front shaping optics the focusability of laser pulses compressed in this way can be partially preserved.

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Capotondi, F., L. Foglia, M. Kiskinova, C. Masciovecchio, R. Mincigrucci, D. Naumenko, E. Pedersoli, A. Simoncig, and F. Bencivenga. "Characterization of ultrafast free-electron laser pulses using extreme-ultraviolet transient gratings." Journal of Synchrotron Radiation 25, no. 1 (January 1, 2018): 32–38. http://dx.doi.org/10.1107/s1600577517015612.

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The characterization of the time structure of ultrafast photon pulses in the extreme-ultraviolet (EUV) and soft X-ray spectral ranges is of high relevance for a number of scientific applications and photon diagnostics. Such measurements can be performed following different strategies and often require large setups and rather high pulse energies. Here, high-quality measurements carried out by exploiting the transient grating process,i.e.a third-order non-linear process sensitive to the time-overlap between two crossed EUV pulses, is reported. From such measurements it is possible to obtain information on both the second-order intensity autocorrelation function and on the coherence length of the pulses. It was found that the pulse energy density needed to carry out such measurements on solid state samples can be as low as a few mJ cm−2. Furthermore, the possibility to control the arrival time of the crossed pulses independently might permit the development of a number of coherent spectroscopies in the EUV and soft X-ray regime, such as, for example, photon echo and two-dimensional spectroscopy.

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Wang, Tao, Jin Wang, Jian Wu, Pengfei Ma, Rongtao Su, Yanxing Ma, and Pu Zhou. "Near-Infrared Optical Modulation for Ultrashort Pulse Generation Employing Indium Monosulfide (InS) Two-Dimensional Semiconductor Nanocrystals." Nanomaterials 9, no. 6 (June 7, 2019): 865. http://dx.doi.org/10.3390/nano9060865.

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In recent years, metal chalcogenide nanomaterials have received much attention in the field of ultrafast lasers due to their unique band-gap characteristic and excellent optical properties. In this work, two-dimensional (2D) indium monosulfide (InS) nanosheets were synthesized through a modified liquid-phase exfoliation method. In addition, a film-type InS-polyvinyl alcohol (PVA) saturable absorber (SA) was prepared as an optical modulator to generate ultrashort pulses. The nonlinear properties of the InS-PVA SA were systematically investigated. The modulation depth and saturation intensity of the InS-SA were 5.7% and 6.79 MW/cm2, respectively. By employing this InS-PVA SA, a stable, passively mode-locked Yb-doped fiber laser was demonstrated. At the fundamental frequency, the laser operated at 1.02 MHz, with a pulse width of 486.7 ps, and the maximum output power was 1.91 mW. By adjusting the polarization states in the cavity, harmonic mode-locked phenomena were also observed. To our knowledge, this is the first time an ultrashort pulse output based on InS has been achieved. The experimental findings indicate that InS is a viable candidate in the field of ultrafast lasers due to its excellent saturable absorption characteristics, which thereby promotes the ultrafast optical applications of InX (X = S, Se, and Te) and expands the category of new SAs.

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Hoff, Dominik, Michael Krüger, Lothar Maisenbacher, A. Max Sayler, Peter Hommelhoff, and Gerhard G. Paulus. "Tracing the phase of focused broadband laser pulses." EPJ Web of Conferences 205 (2019): 01023. http://dx.doi.org/10.1051/epjconf/201920501023.

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We present a three-dimensional measurement of the local focal phase in a focused broadband Gaussian laser beam and find strong deviations from the commonly assumed Gouy phase, with wide ramifications for ultrafast physics.

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Yang, Jinfeng, Kazuki Gen, Nobuyasu Naruse, Shouichi Sakakihara, and Yoichi Yoshida. "A Compact Ultrafast Electron Diffractometer with Relativistic Femtosecond Electron Pulses." Quantum Beam Science 4, no. 1 (January 20, 2020): 4. http://dx.doi.org/10.3390/qubs4010004.

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We have developed a compact relativistic femtosecond electron diffractometer with a radio-frequency photocathode electron gun and an electron lens system. The electron gun generated 2.5-MeV-energy electron pulses with a duration of 55 ± 5 fs containing 6.3 × 104 electrons per pulse. Using these pulses, we successfully detected high-contrast electron diffraction images of single crystalline, polycrystalline, and amorphous materials. An excellent spatial resolution of diffraction images was obtained as 0.027 ± 0.001 Å−1. In the time-resolved electron diffraction measurement, a laser-excited ultrafast electronically driven phase transition in single-crystalline silicon was observed with a temporal resolution of 100 fs. The results demonstrate the advantages of the compact relativistic femtosecond electron diffractometer, including access to high-order Bragg reflections, single shot imaging with the relativistic femtosecond electron pulse, and the feasibility of time-resolved electron diffraction to study ultrafast structural dynamics.

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Hajima, Ryoichi. "Few-Cycle Infrared Pulse Evolving in FEL Oscillators and Its Application to High-Harmonic Generation for Attosecond Ultraviolet and X-ray Pulses." Atoms 9, no. 1 (February 24, 2021): 15. http://dx.doi.org/10.3390/atoms9010015.

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Generation of few-cycle optical pulses in free-electron laser (FEL) oscillators has been experimentally demonstrated in FEL facilities based on normal-conducting and superconducting linear accelerators. Analytical and numerical studies have revealed that the few-cycle FEL lasing can be explained in the frame of superradiance, cooperative emission from self-bunched systems. In the present paper, we review historical remarks of superradiance FEL experiments in short-pulse FEL oscillators with emphasis on the few-cycle pulse generation and discuss the application of the few-cycle FEL pulses to the scheme of FEL-HHG, utilization of infrared FEL pulses to drive high-harmonic generation (HHG) from gas and solid targets. The FEL-HHG enables one to explore ultrafast science with attosecond ultraviolet and X-ray pulses with a MHz repetition rate, which is difficult with HHG driven by solid-state lasers. A research program has been launched to develop technologies for the FEL-HHG and to conduct a proof-of-concept experiment of FEL-HHG.

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Jeanty, Michelet, V. Kartazaev, M. Sharonov, A. Bykov, and R. R. Alfano. "Ultrafast laser pulses generated from the chromium-doped cunyite laser." Optics Communications 284, no. 5 (March 2011): 1339–41. http://dx.doi.org/10.1016/j.optcom.2010.11.015.

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Ischenko, A. A., Yu I. Tarasov, E. A. Ryabov, S. A. Aseyev, and L. Schäfer. "ULTRAFAST TRANSMISSION ELECTRON MICROSCOPY." Fine Chemical Technologies 12, no. 1 (February 28, 2017): 5–25. http://dx.doi.org/10.32362/2410-6593-2017-12-1-5-25.

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Ultrafast laser spectral and electron diffraction methods complement each other and open up new possibilities in chemistry and physics to light up atomic and molecular motions involved in the primary processes governing structural transitions. Since the 1980s, scientific laboratories in the world have begun to develop a new field of research aimed at this goal. “Atomic-molecular movies” will allow visualizing coherent dynamics of nuclei in molecules and fast processes in chemical reactions in real time. Modern femtosecond and picosecond laser sources have made it possible to significantly change the traditional approaches using continuous electron beams, to create ultrabright pulsed photoelectron sources, to catch ultrafast processes in the matter initiated by ultrashort laser pulses and to achieve high spatio-temporal resolution in research. There are several research laboratories all over the world experimenting or planning to experiment with ultrafast electron diffraction and possessing electron microscopes adapted to operate with ultrashort electron beams. It should be emphasized that creating a new-generation electron microscope is of crucial importance, because successful realization of this project demonstrates the potential of leading national research centers and their ability to work at the forefront of modern science.

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Petris, Adrian, Petronela Gheorghe, Tudor Braniste, and Ion Tiginyanu. "Ultrafast Third-Order Nonlinear Optical Response Excited by fs Laser Pulses at 1550 nm in GaN Crystals." Materials 14, no. 12 (June 10, 2021): 3194. http://dx.doi.org/10.3390/ma14123194.

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The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined.

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Tawfik, Walid. "Precise measurement of ultrafast laser pulses using spectral phase interferometry for direct electric-field reconstruction." Journal of Nonlinear Optical Physics & Materials 24, no. 04 (December 2015): 1550040. http://dx.doi.org/10.1142/s021886351550040x.

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In this work, I present a novel method for measuring the pulse duration of few-cycle pulses using spectral phase interferometry for direct electric-field reconstruction (SPIDER) with high accuracy. These few-cycle pulses were generated due to nonlinear self-phase modulation (SPM) in nonlinear medium (neon gas) using a one meter hollow-fiber. The observed reconstructed pulse intensity autocorrelation function was varied from 5.35[Formula: see text]fs to almost 13[Formula: see text]fs. Moreover, the applied method allows for direct controlling of the output pulse duration through variation of the pulse-width of input pulses at different pressure of neon gas. The observed results indicate that the SPM was enhanced for high neon pressure (2.5[Formula: see text]atm.) and short input pluses (32[Formula: see text]fs) without chirping. The obtained results may give an opportunity to monitor and control ultrafast transit interaction in femtosecond chemistry.

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Pawliszewska, Maria, Dorota Tomaszewska, Grzegorz Soboń, Anna Dużyńska, Mariusz Zdrojek, and Jarosław Sotor. "Broadband Metallic Carbon Nanotube Saturable Absorber for Ultrashort Pulse Generation in the 1500–2100 nm Spectral Range." Applied Sciences 11, no. 7 (April 1, 2021): 3121. http://dx.doi.org/10.3390/app11073121.

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Herein, we report on the possibility of ultrashort laser pulse generation in the broadband spectral range using a saturable absorber based on free-standing metallic carbon nanotube thin film. Erbium, thulium, and holmium-doped all-fiber lasers were mode-locked with a single saturable absorber containing a 300 nm thick material layer. Subpicosecond pulses were generated at 1559, 1938, and 2082 nm. Our work validates the broadband operation of metallic carbon nanotube-based saturable absorbers and highlights the suitable performance of nanomatematerial for ultrafast photonic applications.

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Kojima, Yasuhiro, Yuta Masaki, and Fumihiko Kannari. "Control of ultrafast plasmon pulses by spatiotemporally phase-shaped laser pulses." Journal of the Optical Society of America B 33, no. 12 (November 10, 2016): 2437. http://dx.doi.org/10.1364/josab.33.002437.

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Kern, Christian, Michael Zürch, and Christian Spielmann. "Limitations of Extreme Nonlinear Ultrafast Nanophotonics." Nanophotonics 4, no. 3 (January 1, 2015): 303–23. http://dx.doi.org/10.1515/nanoph-2015-0013.

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Abstract High-harmonic generation (HHG) has been established as an indispensable tool in optical spectroscopy. This effect arises for instance upon illumination of a noble gas with sub-picosecond laser pulses at focussed intensities significantly greater than 1012W/cm2. HHG provides a coherent light source in the extreme ultraviolet (XUV) spectral region, which is of importance in inner shell photo ionization of many atoms and molecules. Additionally, it intrinsically features light fields with unique temporal properties. Even in its simplest realization, XUV bursts of sub-femtosecond pulse lengths are released. More sophisticated schemes open the path to attosecond physics by offering single pulses of less than 100 attoseconds duration. Resonant optical antennas are important tools for coupling and enhancing electromagnetic fields on scales below their free-space wavelength. In a special application, placing field-enhancing plasmonic nano antennas at the interaction site of an HHG experiment has been claimed to boost local laser field strengths, from insufficient initial intensities to sufficient values. This was achieved with the use of arrays of bow-tie-shaped antennas of ∼ 100nm in length. However, the feasibility of this concept depends on the vulnerability of these nano-antennas to the still intense driving laser light.We show, by looking at a set of exemplary metallic structures, that the threshold fluence Fth of laser-induced damage (LID) is a greatly limiting factor for the proposed and tested schemes along these lines.We present our findings in the context of work done by other groups, giving an assessment of the feasibility and effectiveness of the proposed scheme.

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Jin, Xinxin, Guohua Hu, Meng Zhang, Tom Albrow-Owen, Zheng Zheng, and Tawfique Hasan. "Environmentally stable black phosphorus saturable absorber for ultrafast laser." Nanophotonics 9, no. 8 (January 28, 2020): 2445–49. http://dx.doi.org/10.1515/nanoph-2019-0524.

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AbstractBlack phosphorus (BP) attracts huge interest in photonic and optoelectronic applications ranging from passive switch for ultrafast lasers to photodetectors. However, the instability of chemically unfunctionalized BP in ambient environment due to oxygen and moisture remains a critical barrier to its potential applications. Here, the parylene-C layer was used to protect inkjet-printed BP-saturable absorbers (BP-SA), and the efficacy of this passivation layer was demonstrated on the stable and continuous operation of inkjet-printed BP-SA in harsh environmental conditions. BP-SA was integrated in an erbium-doped ring laser cavity and immersed in water at ~60°C during operation for investigation. Mode-locked pulses at ~1567.3 nm with ~538 fs pulse width remained stable for >200 h. The standard deviation of spectral width, central wavelength, and pulse width were 0.0248 nm, 0.0387 nm, and 2.3 fs, respectively, in this period, underscoring the extreme stability of BP-SA against high temperature and humidity. This approach could enable the exploitation of BP-based devices for photonic applications when operating under adverse environmental conditions.

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Xue, Bing, Atsushi Yabushita, and Takayoshi Kobayashi. "Ultrafast dynamics of uracil and thymine studied using a sub-10 fs deep ultraviolet laser." Physical Chemistry Chemical Physics 18, no. 25 (2016): 17044–53. http://dx.doi.org/10.1039/c5cp07861j.

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Sharma, N., N. Destouches, C. Florian, R. Serna, and J. Siegel. "Tailoring metal-dielectric nanocomposite materials with ultrashort laser pulses for dichroic color control." Nanoscale 11, no. 40 (2019): 18779–89. http://dx.doi.org/10.1039/c9nr06763a.

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Tang, Mincheng, Rezki Becheker, Pierre-Henry Hanzard, Aleksey Tyazhev, Jean-Louis Oudar, Arnaud Mussot, Alexandre Kudlinski, Thomas Godin, and Ammar Hideur. "Low Noise High-Energy Dissipative Soliton Erbium Fiber Laser for Fiber Optical Parametric Oscillator Pumping." Applied Sciences 8, no. 11 (November 5, 2018): 2161. http://dx.doi.org/10.3390/app8112161.

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We report on a mode-locked erbium-doped fiber laser delivering highly-chirped pulses with several tens of nanojoules of energy around 1560 nm and its exploitation to efficiently pump a fiber optical parametric oscillator (FOPO), thus enabling picosecond pulse generation around 1700 nm. The laser cavity features a high normal dispersion and mode-locking is sustained using tailored spectral filtering combined with nonlinear polarization evolution and a semiconductor saturable absorber. Numerical simulations show that the laser dynamics is governed by a strong mode-locking mechanism compensating for the large spectral and temporal pulse evolution along the cavity. In the frame of high energy picosecond pulse generation around 1700 nm, we then demonstrate that using highly-chirped pulses as pump pulses allows for the efficient tuning of the FOPO idler wavelength between 1620 and 1870 nm. In addition, satisfying noise characteristics have been achieved both for the Er-laser and the FOPO, with respective relative intensity noises (RIN) of −154 and −140 dBc/Hz, thus paving the way for the use of such sources in ultrafast instrumentation.

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Mincigrucci, Riccardo, Filippo Bencivenga, Emiliano Principi, Flavio Capotondi, Laura Foglia, Denys Naumenko, Alberto Simoncig, et al. "Timing methodologies and studies at the FERMI free-electron laser." Journal of Synchrotron Radiation 25, no. 1 (January 1, 2018): 44–51. http://dx.doi.org/10.1107/s1600577517016368.

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Time-resolved investigations have begun a new era of chemistry and physics, enabling the monitoring in real time of the dynamics of chemical reactions and matter. Induced transient optical absorption is a basic ultrafast electronic effect, originated by a partial depletion of the valence band, that can be triggered by exposing insulators and semiconductors to sub-picosecond extreme-ultraviolet pulses. Besides its scientific and fundamental implications, this process is very important as it is routinely applied in free-electron laser (FEL) facilities to achieve the temporal superposition between FEL and optical laser pulses with tens of femtoseconds accuracy. Here, a set of methodologies developed at the FERMI facility based on ultrafast effects in condensed materials and employed to effectively determine the FEL/laser cross correlation are presented.

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Nakajima, Takashi. "Ultrafast Spin-Polarization Induced by Short Laser Pulses." Review of Laser Engineering 36, Supplement (2008): 12–13. http://dx.doi.org/10.2184/lsj.36.12.

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Bigot, Jean-Yves, Mircea Vomir, and Eric Beaurepaire. "Coherent ultrafast magnetism induced by femtosecond laser pulses." Nature Physics 5, no. 7 (May 31, 2009): 515–20. http://dx.doi.org/10.1038/nphys1285.

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Murnane, M. M., H. C. Kapteyn, and R. W. Falcone. "High-Density Plasmas Produced by Ultrafast Laser Pulses." Physical Review Letters 62, no. 2 (January 9, 1989): 155–58. http://dx.doi.org/10.1103/physrevlett.62.155.

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Journal articles on the topic 'Ultrafast Laser pulses'

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