Journal articles: 'Laser plaama'

1

Lou, Qihong. "UV excimer laser produced plasma and it's application to laser plasma switching." Laser and Particle Beams 6, no. 2 (May 1988): 335–41. http://dx.doi.org/10.1017/s0263034600004092.

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The characteristics of a laser plasma created by a high intensity UV excimer laser were investigated. The UV laser plasma was used as a switch for control of the laser pulse duration for the first time. An X-ray preionized XeCl laser pulse duration can be changed from 10 to 85 ns. This technique is useful for many applications of excimer lasers requiring various pulse durations.

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2

Grigorian, Galina M., and Adam Cenian. "Influence of nitrogen on CO-laser characteristics." Photonics Letters of Poland 9, no. 2 (July 1, 2017): 69. http://dx.doi.org/10.4302/plp.v9i2.675.

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The role of the addition of nitrogen to the discharge plasma of CO lasers on plasma-chemical processes is discussed here. It is shown that nitrogen addition improves laser characteristics and changes the composition of the laser active medium. A reduction of CO highly-excited vibrational-states populations with current is smaller in the case of mixtures with nitrogen additions. The addition of nitrogen significantly decreases CO dissociation level and concentrations of C atoms created in plasma-chemical reactions of laser discharge. Full Text: PDF ReferencesG.M. Grigorian and I.V. Kochetov, "Balance of CO molecules in the plasma of a sealed-off CO laser", Plasma Phys. Rep. 30, 788 (2004). CrossRef V.S. Aleinikov and V.I. Masychev, CO Lasers (Moscow, Radio i Svyaz' 1990).A. Cenian, A. Chernukho, V. Borodin and G.Śliwiński, "Modeling of Plasma-Chemical Reactions in Gas Mixture of CO2 Lasers I. Gas Decomposition in Pure CO2 Glow Discharge", Contr. Plasma Phys. 34, 25 (1994). CrossRef A. Cenian, A. Chernukho, V. Borodin, "Modeling of Plasma-Chemical Reactions in Gas Mixture of CO2 lasers. II. Theoretical Model and its Verification", Contrib. Plasma Phys. 35, 273 (1995). CrossRef A. Cenian, A. Chernukho, P. Kukiełło, R. Zaremba, V. Borodin and G. Śliwiński, "Improvement of self-regeneration of gas mixtures in a convection-cooled 1.2 kW laser", J.Phys. D: Appl.Phys. 30, 1103 (1997). CrossRef E.A. Trubacheev, Trudy FIAN 102, 3 (1977).G.M. Grigorian, B.M. Dymshits and Yu.Z. Ionikh, "Influence of oxygen on the parameters of the active medium in an electric-discharge CO laser", Sov J Quant Electron 19, 889 (1989). CrossRef V.N. Ochkin, S.Yu. Savinov, N.N. Sobolev and E.A. Trubacheev, Kvant. Elektr. 1, 573 (1974).

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Křivková, Anna, Vojtěch Laitl, Elias Chatzitheodoridis, Lukáš Petera, Petr Kubelík, Antonín Knížek, Homa Saeidfirozeh, et al. "Morphology of Meteorite Surfaces Ablated by High-Power Lasers: Review and Applications." Applied Sciences 12, no. 10 (May 11, 2022): 4869. http://dx.doi.org/10.3390/app12104869.

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Under controlled laboratory conditions, lasers represent a source of energy with well-defined parameters suitable for mimicking phenomena such as ablation, disintegration, and plasma formation processes that take place during the hypervelocity atmospheric entry of meteoroids. Furthermore, lasers have also been proposed for employment in future space exploration and planetary defense in a wide range of potential applications. This highlights the importance of an experimental investigation of lasers’ interaction with real samples of interplanetary matter: meteorite specimens. We summarize the results of numerous meteorite laser ablation experiments performed by several laser sources—a femtosecond Ti:Sapphire laser, the multislab ceramic Yb:YAG Bivoj laser, and the iodine laser known as PALS (Prague Asterix Laser System). The differences in the ablation spots’ morphology and their dependence on the laser parameters are examined via optical microscopy, scanning electron microscopy, and profilometry in the context of the meteorite properties and the physical characteristics of laser-induced plasma.

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Hematizadeh, A., F. Bakhtiari, S. M. Jazayeri, and B. Ghafary. "Strong terahertz radiation generation by beating of two laser beams in magnetized overdense plasma." Laser and Particle Beams 34, no. 3 (July 22, 2016): 527–32. http://dx.doi.org/10.1017/s0263034616000410.

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AbstractTerahertz (THz) radiation generation by nonlinear mixing of two laser beams, obliquely incident on an overdense plasma is investigated. In an overdense plasma, the laser beams penetrate to only thin layer of a plasma surface and reflected. At this thin layer, the laser beams exert a ponderomotive force on the electrons of plasma and impart them oscillatory velocity at the different frequency of lasers. THz waves appear in the reflected component from the plasma surface. The amplitude of THz waves can be augmented by applying the magnetic field perpendicular to the direction of propagation of lasers. It is found that the field strength of the emitted THz radiations is sensitive to the angle of incident of the laser beams, beat frequency, and magnetic field strength. In this scheme, the magnetic field strength plays an important role for strong THz wave generation.

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Hematizadeh, A., S. M. Jazayeri, and B. Ghafary. "Generation of terahertz radiation by beating of two laser beams in collisional magnetized plasma." Laser and Particle Beams 34, no. 4 (August 30, 2016): 569–75. http://dx.doi.org/10.1017/s0263034616000513.

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AbstractThis paper presents analytical calculations for terahertz (THz) radiation by beating of two cosh-Gaussian laser beams in a density rippled collisional magnetized plasma. Lasers beams exert a ponderomotive force on the electrons of plasma in beating frequency which generates THz waves. The magnetic field was considered parallel to the direction of lasers which leads to propagate right-hand circularly polarized or left-hand circularly polarized waves in the plasma depending on the phase matching conditions. Effects of collision frequency, decentered parameter of lasers and the magnetic field strength are analyzed for THz radiation generation. By the optimization of laser and plasma parameters, the efficiency of order 27% can be achieved.

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6

Bingham, Robert. "Basic concepts in plasma accelerators." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1840 (February 2006): 559–75. http://dx.doi.org/10.1098/rsta.2005.1722.

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In this article, we present the underlying physics and the present status of high gradient and high-energy plasma accelerators. With the development of compact short pulse high-brightness lasers and electron and positron beams, new areas of studies for laser/particle beam–matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultra-high-acceleration gradients. These include the plasma beat wave accelerator (PBWA) mechanism which uses conventional long pulse (∼100 ps) modest intensity lasers ( I ∼10 14 –10 16 W cm −2 ), the laser wakefield accelerator (LWFA) which uses the new breed of compact high-brightness lasers (<1 ps) and intensities >10 18 W cm −2 , self-modulated laser wakefield accelerator (SMLWFA) concept which combines elements of stimulated Raman forward scattering (SRFS) and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches the plasma wakefield accelerator. In the ultra-high intensity regime, laser/particle beam–plasma interactions are highly nonlinear and relativistic, leading to new phenomenon such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm −1 have been generated with monoenergetic particle beams accelerated to about 100 MeV in millimetre distances recorded. Plasma wakefields driven by both electron and positron beams at the Stanford linear accelerator centre (SLAC) facility have accelerated the tail of the beams.

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JUNGWIRTH, K. "Recent highlights of the PALS research program." Laser and Particle Beams 23, no. 2 (June 2005): 177–82. http://dx.doi.org/10.1017/s0263034605050317.

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The Prague Asterix Laser System (PALS) research program covers a broad spectrum of laser–plasma experiments in the range of power densities of 1014-5 × 1016W/cm2, aimed at development and applications of laser plasma-based ion and soft X-ray sources of plasma based ultra-bright XUV lasers in particular. In parallel to these two main lines of research, various principal tasks of laser plasma physics are being studied, such as generation and propagation of laser-induced shock waves, laser ablation, and crater creation processes or laser imprint treatment. Results selected of numerous experimental projects performed at PALS within the period 2002–2004 are surveyed in the paper, experiments with intense soft XUV laser beams being highlighted on the first place.

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8

Tan, Chao, Binliang Hu, Shiping Zhan, Yonghua Hu, and Bin Zhong. "All-Optical Switching Based on the Plasma Channel Induced by Laser Pulses." Advances in Condensed Matter Physics 2018 (October 1, 2018): 1–7. http://dx.doi.org/10.1155/2018/9621953.

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We display a theoretical and experimental study of all-optical switching for signal lasers based on the plasma channel induced by the control laser. Using the plasma channel generated in the carbon disulfide (CS2) solution, the signal light can be modulated as some spatial distributions including unchanging, ring-shaped beam, and other intensity profiles. The modulation on the signal light can be conveniently adjusted by changing the control light’s incident intensity distribution. We can infer the dark spot shape in the modulated signal laser through the intensity profile of control laser beam. These results provide the great potential of plasma channel induced by lasers as an all-optical switching for various optoelectronic applications.

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9

Grigorian, Galina M., and Adam Cenian. "Influence of nitrogen on thermodynamic properties and plasma composition in discharge tube of CO-laser." Archives of Thermodynamics 37, no. 3 (September 1, 2016): 31–43. http://dx.doi.org/10.1515/aoter-2016-0018.

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Abstract The role of the addition of nitrogen to the discharge plasma of CO lasers on thermodynamic properties and composition of the laser active medium is discussed here. It is shown that nitrogen addition improves laser characteristics and changes the composition of the laser active medium. The addition of nitrogen significantly decreases CO dissociation level and concentrations of C atoms created in plasma-chemical reactions of laser discharge.

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10

Geng, Congrui, Jixing Cai, Yubo Liu, Zequn Zhang, Hongtao Mao, Hao Yu, and Yunpeng Wang. "Study on the Expansion Kinetics of Plasma and Absorption Wave Induced by Millisecond-Nanosecond Combined Pulse Lasers in Fused Quartz." Photonics 10, no. 4 (April 6, 2023): 411. http://dx.doi.org/10.3390/photonics10040411.

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The transient temperature field, the velocity and pressure of plasma, and the absorption wave of fused quartz induced by millisecond-nanosecond combined pulse lasers are simulated. The theoretical model of plasma and absorption wave produced by fused quartz irradiated by a millisecond-nanosecond pulsed laser is established, in which pulse delay and laser energy are essential variables. The results show that the damaged effect of the millisecond-nanosecond combined pulse laser is different under the damaged effect of different pulse delay conditions. When the energy densities of millisecond-nanosecond combined pulse lasers are 800 J/cm2 and 20 J/cm2, respectively, the range of pulse delay is 0 ms < Δt ≤ 3 ms, and the energy coupling efficiency is the highest when Δt = 1 ms. The addition of a nanosecond pulsed laser causes more obvious thermal damage and optical breakdown to fused quartz. The high pressure is concentrated at the plasma expansion interface or the shock wave front. The results can optimize the simulation parameters and be applied to laser plasma processing technology.

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11

Drake, R. Paul. "Laser–plasma-interaction experiments using multikilojoule lasers." Laser and Particle Beams 6, no. 2 (May 1988): 235–44. http://dx.doi.org/10.1017/s0263034600003980.

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This paper summarizes the results of several laser–plasma-interaction experiments using multikilojoule lasers, and considers their implications for laser fusion. The experiments used 1·06-, 0·53-, 0·35-, and 0·26-μm light to produce relatively large, warm, planar plasmas and to study the effect of laser wavelength and density-gradient scale length on the Stimulated Raman Scattering and on the scattering of light at frequencies near the incident laser frequencey by Stimulated Brillouin Scattering or other processes. The results of these experiments suggest that some laser wavelength between 0·2 and 0·6 μm will be required for high-gain laser fusion.

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12

Siders, Galvin, Erlandson, Bayramian, Reagan, Sistrunk, Spinka, and Haefner. "Wavelength Scaling of Laser Wakefield Acceleration for the EuPRAXIA Design Point." Instruments 3, no. 3 (August 21, 2019): 44. http://dx.doi.org/10.3390/instruments3030044.

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Scaling the particle beam luminosity from laser wakefield accelerators to meet the needs of the physics community requires a significant, thousand-fold increase in the average power of the driving lasers. Multipulse extraction is a promising technique capable of scaling high peak power lasers by that thousand-fold increase in average power. However, several of the best candidate materials for use in multipulse extraction amplifiers lase at wavelengths far from the 0.8–1.0 μm region which currently dominates laser wakefield research. In particular, we have identified Tm:YLF, which lases near 1.9 µm, as the most promising candidate for high average power multipulse extraction amplifiers. Current schemes to scale the laser, plasma, and electron beam parameters to alternative wavelengths are unnecessarily restrictive in that they stress laser performance gains to keep plasma conditions constant. In this paper, we present a new and more general scheme for wavelength scaling a laser wakefield acceleration (LWFA) design point that provides greater flexibility in trading laser, plasma, and electron beam parameters within a particular design point. Finally, a multipulse extraction 1.9 µm Tm:YLF laser design meeting the EuPRAXIA project’s laser goals is discussed.

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13

CHAUHAN, P. K., S. T. MAHMOUD, R. P. SHARMA, and H. D. PANDEY. "Effect of laser ripple on the beat wave excitation and particle acceleration." Journal of Plasma Physics 73, no. 1 (February 2007): 117–30. http://dx.doi.org/10.1017/s002237780600465x.

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Abstract.This paper presents the effect of ripple on the plasma wave excitation process and acceleration of electrons in a laser produced plasma. The plasma wave is generated by the beating of two coaxial lasers of frequencies ω1 and ω2, such that ω1-ω2≅ωp. One of the main laser beams also has intensity spikes. The nonlinearity due to the relativistic mass variation depends not only on the intensity of one laser beam but also on the second laser beam. Therefore the behavior of the first laser beam affects the second laser beam, hence cross-focusing takes place. Owing to the interaction of ripple and the main laser beams, the ripple grows inside the plasma. The behavior of the ripple in the plasma affects the excitation of the electron plasma wave as well as the electron acceleration. The amplitude of the electron plasma wave and the electron energy are calculated, in the presence of ripple.

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14

Kline, J. L., D. S. Montgomery, C. Rousseaux, S. D. Baton, V. Tassin, R. A. Hardin, K. A. Flippo, et al. "Investigation of stimulated Raman scattering using a short-pulse diffraction limited laser beam near the instability threshold." Laser and Particle Beams 27, no. 1 (February 18, 2009): 185–90. http://dx.doi.org/10.1017/s0263034609000251.

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AbstractShort pulse laser plasma interaction experiments using diffraction limited beams provide an excellent platform to investigate the fundamental physics of stimulated Raman scattering. Detailed understanding of these laser plasma instabilities impacts the current inertial confinement fusion ignition designs and could potentially impact fast ignition when higher energy lasers are used with longer pulse durations (>1 kJ and >1 ps). Using short laser pulses, experiments can be modeled over the entire interaction time of the laser using particle-in-cell codes to validate our understanding quantitatively. Experiments have been conducted at the Trident laser facility and the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) to investigate stimulated Raman scattering near the threshold of the instability using 527 nm and 1059 nm laser light, respectively, with 1.5–3.0 ps pulses. In both experiments, the interaction beam was focused into pre-ionized helium gas-jet plasma. Measurements of the reflectivity as a function of intensity and kλD were completed at the Trident laser facility, where k is the electron plasma wave number and λD is the plasma Debye length. At LULI, a 300 fs Thomson scattering probe is used to directly measure the density fluctuations of the driven electron plasma and ion acoustic waves. Work is currently underway comparing the results of the experiments with simulations using the VPIC particle-in-cell code. Details of the experimental results are presented in this manuscript.

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15

Geng, Pan-Fei, Min Chen, Xin-Zhe Zhu, Wei-Yuan Liu, Zheng-Ming Sheng, and Jie Zhang. "Propagation of axiparabola-focused laser pulses in uniform plasmas." Physics of Plasmas 29, no. 11 (November 2022): 112301. http://dx.doi.org/10.1063/5.0109643.

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An axiparabola-based flying focus laser possesses a long focal depth, a small focal spot, and a controllable group velocity. It has been proposed for wide applications, such as phase-locked laser wakefield acceleration and photon acceleration. We numerically study the propagation of axiparabola-focused laser pulses in plasmas and find that such lasers can propagate stably over long distances in plasmas at low intensity. When the laser intensity increases to the relativistic intensity, they no longer propagate stably. Pulse front deformation and fracture appear due to the formation of plasma density modulations. We propose three schemes to mitigate the unstable propagation of axiparabola-focused lasers: (i) adding a radially dependent pulse front delay, (ii) placing the plasma away from the beginning of the focal line, and (iii) using an axiparabola mirror with a negative focal line. All these methods are relatively easy to implement. Our studies can provide guidance for applications of axiparabola-focused lasers.

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Wang, Wei-Min, Zheng-Ming Sheng, Yu-Tong Li, and Jie Zhang. "Upper-limit power for self-guided propagation of intense lasers in underdense plasma." High Power Laser Science and Engineering 1, no. 2 (August 30, 2013): 74–79. http://dx.doi.org/10.1017/hpl.2013.12.

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AbstractIt is found that there is an upper-limit critical power for self-guided propagation of intense lasers in plasma in addition to the well-known lower-limit critical power set by the relativistic effect. Above this upper-limit critical power, the laser pulse experiences defocusing due to expulsion of local plasma electrons by the transverse ponderomotive force. Associated with the upper-limit power, a lower-limit critical plasma density is also found for a given laser spot size, below which self-focusing does not occur for any laser power. Both the upper-limit power and the lower-limit density are derived theoretically and verified by two-dimensional particle-in-cell simulations. The present study provides new guidance for experimental designs, where self-guided propagation of lasers is essential.

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Deng, Hongyang, Ziyang Zhang, Min Chen, Jianlong Li, Qiang Cao, and Xuejiao Hu. "Femtosecond Laser Fabrication of Curved Plasma Channels with Low Surface Roughness and High Circularity for Multistage Laser-Wakefield Accelerators." Materials 16, no. 8 (April 21, 2023): 3278. http://dx.doi.org/10.3390/ma16083278.

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A multistage laser-wakefield accelerator with curved plasma channels was proposed to accelerate electrons to TeV energy levels. In this condition, the capillary is discharged to produce plasma channels. The channels will be used as waveguides to guide intense lasers to drive wakefields inside the channel. In this work, a curved plasma channel with low surface roughness and high circularity was fabricated by a femtosecond laser ablation method based on response surface methodology. The details of the fabrication and performance of the channel are introduced here. Experiments show that such a channel can be successfully used to guide lasers, and electrons with an energy of 0.7 GeV were achieved.

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18

Dzelzainis, T., G. Nersisyan, D. Riley, L. Romagnani, H. Ahmed, A. Bigongiari, M. Borghesi, et al. "The TARANIS laser: A multi-Terawatt system for laser-plasma investigations." Laser and Particle Beams 28, no. 3 (July 30, 2010): 451–61. http://dx.doi.org/10.1017/s0263034610000467.

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AbstractThe multi-Terawatt laser system, terawatt apparatus for relativistic and nonlinear interdisciplinary science, has been recently installed in the Centre for Plasma Physics at the Queen's University of Belfast. The system will support a wide ranging science program, which will include laser-driven particle acceleration, X-ray lasers, and high energy density physics experiments. Here we present an overview of the laser system as well as the results of preliminary investigations on ion acceleration and X-ray lasers, mainly carried out as performance tests for the new apparatus. We also discuss some possible experiments that exploit the flexibility of the system in delivering pump-probe capability.

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19

Sadighi-Bonabi, R., H. Hora, Z. Riazi, E. Yazdani, and S. K. Sadighi. "Generation of plasma blocks accelerated by nonlinear forces from ultraviolet KrF laser pulses for fast ignition." Laser and Particle Beams 28, no. 1 (March 2010): 101–7. http://dx.doi.org/10.1017/s0263034609990656.

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AbstractHere we report on the production of highly directed ion blocks by plasma interaction of ultraviolet wavelength light produced from a KrF laser. This may support the requirement to produce a fast ignition deuterium-tritium fusion at densities not much higher than the solid state by a single shot petawatt-picoseconds ultraviolet laser pulse. Using double Rayleigh initial density profiles, we are studying numerically how the nonlinear force necessary to accelerate plasma blocks may reach the highest possible thickness. Propagation of plasma blocks and the volumetric hot electrons can be shown in detail. Results of computations for wavelengths of two lasers are compared, which show that the block current density for a KrF laser is approximately four times bigger than for the Nd-glass lasers. This is in good agreement with the number predicted by theory.

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MALKA, V., A. F. LIFSCHITZ, J. FAURE, and Y. GLINEC. "GeV MONOENERGETIC ELECTRON BEAM WITH LASER PLASMA ACCELERATOR." International Journal of Modern Physics B 21, no. 03n04 (February 10, 2007): 277–86. http://dx.doi.org/10.1142/s0217979207042057.

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Laser plasma accelerators produce today ultra short, quasi-monoenergetic and collimated electron beams with potential applications in material science, chemistry and medicine. The laser plasma accelerator used to produce such an electron beam is presented. The design of a laser based accelerator designed to produce more energetic electron beams with a narrow relative energy spread is also proposed here. This compact approach should permit a miniaturization and cost reduction of future accelerators and associated X-Free Electrons Lasers (XFEL).

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Lebo, I. G. "About the modeling of light beam self-focusing in plasma at the irradiation of the target by power UV laser." Russian Technological Journal 9, no. 1 (March 3, 2021): 79–86. http://dx.doi.org/10.32362/2500-316x-2021-9-1-79-86.

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The peculiarities of light beam expansion in plasma upon irradiation of condensed targets with a powerful UV laser pulse are studied with the help of mathematical modeling. Experiments were carried out at the Lebedev Physical Institute of the Russian Academy of Sciences with the use of GARPUN installation: a powerful KrF laser that irradiated two-layer targets consisting of aluminum foil and a plexiglass layer. Channels stretched along the direction of incidence of the laser beam were found at the bottom of the crater. It was shown on the basis of experimental and calculated data that selffocusing of the laser beam developed in the plasma. As a result, hot spots were produced in vicinity of the plasma critical density, and fast (superthermal) electron flows were generated. The electron flows could produce the channels in the plexiglas. In order to describe the self-focusing effect a physicalmathematical model was developed, and “FOCUS” program was created at the Russian Technological University (MIREA). Numerical simulations were carried out on the gas-dynamic profiles (linear and exponential). It was shown that thermal self-focusing could develop at the conditions of “GARPUN” experiments (~ 1 mm longitudinal plasma, moderate radiation intensity: 1011–1012(W/cm2) × µm2). The parameters of dangerous modes of laser beam perturbations were estimated. The interest in the experimental and mathematical modelling results is related to the laser thermonuclear fusion (LTF) research. Although Nd glass lasers are the basic installations for LTF research, UV gas eximer lasers have some advantages as drivers for future thermonuclear fusion reactors. The interaction of UV laser radiation with plasma has some peculiarities. Thus, developing physical-mathematical models and creating new programs required for the interpretation of modern UV laser – plasma coupling experiments and for the design of large scale facilities based on eximer drivers is a topical problem.

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Magesh Kumar, K. K., M. Kumar, T. Yuan, Z. M. Sheng, and M. Chen. "Terahertz radiation from plasma filament generated by two-color laser gas–plasma interaction." Laser and Particle Beams 33, no. 3 (June 10, 2015): 473–79. http://dx.doi.org/10.1017/s0263034615000518.

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AbstractWe develop a theoretical model for terahertz (THz) radiation generation, when an intense short laser pulse (ω1, k1) is mixed with its frequency shifted second harmonic (ω2, k2), where ω2 = 2ω1 + ωT and ωT is in the THz range in the plasma. The lasers exert a ponderomotive force on the electrons and drive density perturbations at (2ω1, 2k1) and (ω2 − ω1, k2 − k1). These density perturbations couple with the oscillatory velocities of the electron due to the lasers and produce a nonlinear current at (ω2 − 2ω1, k2 − 2k1). This current acts as an antenna to produce the THz radiation. The THz power depends upon the square of plasma density and $I_1^2 {I_2}$, where I1 and I2 are the intensities of fundamental and second harmonic laser. The radiation is mainly along the forward direction. Two-dimensional particle-in-cell simulations are used to study the near-field radiation properties.

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Kimura, W. D., N. E. Andreev, M. Babzien, I. Ben-Zvi, D. B. Cline, C. E. Dilley, S. C. Gottschalk, et al. "Inverse free electron lasers and laser wakefield acceleration driven by CO 2 lasers." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1840 (January 24, 2006): 611–22. http://dx.doi.org/10.1098/rsta.2005.1726.

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The staged electron laser acceleration (STELLA) experiment demonstrated staging between two laser-driven devices, high trapping efficiency of microbunches within the accelerating field and narrow energy spread during laser acceleration. These are important for practical laser-driven accelerators. STELLA used inverse free electron lasers, which were chosen primarily for convenience. Nevertheless, the STELLA approach can be applied to other laser acceleration methods, in particular, laser-driven plasma accelerators. STELLA is now conducting experiments on laser wakefield acceleration (LWFA). Two novel LWFA approaches are being investigated. In the first one, called pseudo-resonant LWFA, a laser pulse enters a low-density plasma where nonlinear laser/plasma interactions cause the laser pulse shape to steepen, thereby creating strong wakefields. A witness e -beam pulse probes the wakefields. The second one, called seeded self-modulated LWFA, involves sending a seed e -beam pulse into the plasma to initiate wakefield formation. These wakefields are amplified by a laser pulse following shortly after the seed pulse. A second e -beam pulse (witness) follows the seed pulse to probe the wakefields. These LWFA experiments will also be the first ones driven by a CO 2 laser beam.

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Singh, Rohtash, and V. K. Tripathi. "Laser excitation of terahertz surface plasma wave over a hollow capillary plasma." Laser and Particle Beams 34, no. 1 (December 28, 2015): 109–14. http://dx.doi.org/10.1017/s0263034615001020.

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AbstractTwo collinear laser pulses of finite spot size propagating through a capillary plasma, modeled as a hollow plasma cylinder, are shown to produce beat frequency terahertz (THz) surface plasmons at the inner surface. The evanescent laser fields in the plasma impart oscillatory velocity to electrons and exert a beat ponderomotive force on them. The static component of the ponderomotive force inhibits plasma from filling the vacuum region while the beat frequency component produces a nonlinear current (${\vec J^{{\;\rm NL}}}$) that drives the difference frequency THz surface plasma wave (SPW). Phase matching for the THz surface wave excitation is achieved when the group velocity of the lasers equals the phase velocity of the beat frequency SPW. At laser intensities of ~1014W/cm2at 10 μm wavelength, one may attain normalized surface wave amplitude ~ 0.03.

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Batani, Dimitri. "Short-pulse laser ablation of materials at high intensities: Influence of plasma effects." Laser and Particle Beams 28, no. 2 (March 23, 2010): 235–44. http://dx.doi.org/10.1017/s0263034610000078.

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AbstractThe paper is devoted to the study of plasma effects, which are present in laser ablation at relatively high intensity (I ≥ 1012 W/cm2). We start from the classical “two temperature model” of laser ablation (“cold solid approximation”) and we extend it to higher intensities where laser-induced heating and laser-induced changes in the background material become relevant. The new model is also compared to experimental results on laser ablation of solid targets from short pulse lasers at high intensities (up to 1014 W/cm2). Finally, we consider the effects on laser-ablation of laser-generated fast electrons.

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Offenberger, A. A., J. Santiago, M. Fujita, R. Fedosejevs, and W. Rozmus. "Stimulated scattering from laser produced plasma." Laser and Particle Beams 8, no. 1-2 (January 1990): 153–71. http://dx.doi.org/10.1017/s0263034600007916.

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Stimulated Brillouin and Raman scattering are of considerable interest because of their importance to basic nonlinear plasma physics phenomena and to laser-driven inertial confinement fusion. Induced scattering can be substantial for high intensity (I), long wavelength (λ) lasers because the instability growth rates depend exponentially on Jλ2, and also for short wavelength, long scalelength (L) laser/plasma interaction because of nearly homogeneous or large convective gain conditions. Experimental results from both KrF and CO2 laser/plasma interaction studies are presented to illustrate important wavelength dependent features of induced scattering such as the nature of the instability (absolute, convective), threshold, spectra, reflectivity and saturation effects. Backscattering characteristics have been measured for solid target plasmas (aluminum, gold) produced by KrF laser pulses focused to intensities <1014 W/cm2 and gas targets (hydrogen, oxygen) by CO2 laser pulses at intensities <1013 W/cm2. Collisional absorption dominates the KrF laser experiments, whereas particle heating and increased Landau damping dominate the CO2 laser experiments. Current theoretical work concerned with nonlinear effects in Langmuir wave localization, wave collapse and particle heating (generating characteristic high temperature electrons) is also presented.

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Toci, Guido, Zeudi Mazzotta, Luca Labate, François Mathieu, Matteo Vannini, Barbara Patrizi, and Leonida A. Gizzi. "Conceptual Design of a Laser Driver for a Plasma Accelerator User Facility." Instruments 3, no. 3 (August 8, 2019): 40. http://dx.doi.org/10.3390/instruments3030040.

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The purpose of the European project EuPRAXIA is to realize a novel plasma accelerator user facility. The laser driven approach sets requirements for a very high performance level for the laser system: pulse peak power in the petawatt range, pulse repetition rate of several tens of Hz, very high beam quality and overall stability of the system parameters, along with 24/7 operation availability for experiments. Only a few years ago these performances were considered unrealistic, but recent advances in laser technologies, in particular in the chirped pulse amplification (CPA) of ultrashort pulses and in high energy, high repetition rate pump lasers have changed this scenario. This paper discusses the conceptual design and the overall architecture of a laser system operating as the driver of a plasma acceleration facility for different applications. The laser consists of a multi-stage amplification chain based CPA Ti:Sapphire, using frequency doubled, diode laser pumped Nd or Yb solid state lasers as pump sources. Specific aspects related to the cooling strategy of the main amplifiers, the operation of pulse compressors at high average power, and the beam pointing diagnostics are addressed in detail.

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Garner, Allen L., Bogdan Neculaes, and Dmitry V. Dylov. "Infrared Laser-Based Single Cell Permeabilization by Plasma Membrane Temperature Gradients." Membranes 12, no. 6 (May 31, 2022): 574. http://dx.doi.org/10.3390/membranes12060574.

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Single cell microinjection provides precise tuning of the volume and timing of delivery into the treated cells; however, it also introduces workflow complexity that requires highly skilled operators and specialized equipment. Laser-based microinjection provides an alternative method for targeting a single cell using a common laser and a workflow that may be readily standardized. This paper presents experiments using a 1550 nm, 100 fs pulse duration laser with a repetition rate of 20 ns for laser-based microinjection and calculations of the hypothesized physical mechanism responsible for the experimentally observed permeabilization. Chinese Hamster Ovarian (CHO) cells exposed to this laser underwent propidium iodide uptake, demonstrating the potential for selective cell permeabilization. The agreement between the experimental conditions and the electropermeabilization threshold based on estimated changes in the transmembrane potential induced by a laser-induced plasma membrane temperature gradient, even without accounting for enhancement due to traditional electroporation, strengthens the hypothesis of this mechanism for the experimental observations. Compared to standard 800 nm lasers, 1550 nm fs lasers may ultimately provide a lower cost microinjection method that readily interfaces with a microscope and is agnostic to operator skill, while inducing fewer deleterious effects (e.g., temperature rise, shockwaves, and cavitation bubbles).

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Yu, Chenghao, Jifei Ye, Hao Chang, Weijing Zhou, Xiao Han, Mingyu Li, and Heyan Gao. "Experimental Research on Characteristics of Impulse Coupling and Plasma Plume Generated by Laser Irradiating Copper Target with Nanosecond Pulsed Laser Propulsion." Aerospace 10, no. 6 (June 7, 2023): 544. http://dx.doi.org/10.3390/aerospace10060544.

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The ejection of the plasma plume produced by laser ablation is an important process for inducing mechanical effects. Therefore, in this paper, the characteristics of the plasma plume are investigated in order to analyze the impulse coupling mechanism with two laser spot diameters, 300 μm and 1100 μm, respectively. The impulse generated by laser irradiating the copper target was measured by the torsion pendulum, and the plasma plume was investigated using fast photography and optical emission spectroscopy. The experimental results show that the optimal laser intensity is independent of the beam spot size. However, when the laser intensity is greater than 2.8 × 109 W/cm2, the impulse coupling coefficient with the small beam spot starts to gradually decrease, while that with the large beam spot tends to saturate. Additionally, the stream-like structure and the semi-ellipsoid structure of the plasma plume were observed, respectively. Furthermore, the electron number density was estimated using the Stark broadening method, and the effect of the plasma plume on the impulse coupling coefficient was discussed. The results provide a technical reference for several applications including orbital debris removal with lasers, laser thrusters, and laser despinning.

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Miriam Cheriyan, Renju, Nikhil Varghese, R. S. Sooraj, Kavya H. Rao, and N. Smijesh. "A Comprehensive Review on Amplification of Laser Pulses via Stimulated Raman Scattering and Stimulated Brillouin Scattering in Plasmas." Plasma 5, no. 4 (November 24, 2022): 499–539. http://dx.doi.org/10.3390/plasma5040037.

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The demand for high-intensity lasers has grown ever since the invention of lasers in 1960, owing to their applications in the fields of inertial confinement fusion, plasma-based relativistic particle accelerators, complex X-ray and gamma-ray sources, and laboratory astrophysics. To create such high-intensity lasers, free-running lasers were either Q-switched or mode-locked to increase the peak power to the gigawatt range. Later, chirped pulse amplification was developed, allowing the generation of peak power up to 1012 W. However, the next generation of high-intensity lasers might not be able to be driven by the solid-state technology alone as they are already operating close to their damage thresholds. In this scenario, concepts of amplification based on plasmas has the potential to revolutionize the laser industry, as plasma is already a broken-down medium, and hence does not pose any problems related to the damage thresholds. On the other hand, there are many other aspects that need to be addressed before developing technologies based on plasma-based amplification, and they are being investigated via theoretical and numerical methods and supported by several experiments. In this report, we review the prospects of employing plasma as the medium of amplification by utilising stimulated scattering techniques, such as the stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) techniques, to modulate high-power laser pulses, which would possibly be the key to the next generation of high-power lasers. The 1980s saw the commencement of research in this field, and possibilities of obtaining high peak powers were verified theoretically with the help of numerical calculations and simulations. The extent of amplification by these stimulated scattering schemes are limited by a number of instabilities such as forward Raman scattering (FRS), filamentation, etc., and here, magnetised plasma played an important role in counteracting these parasitic effects. The current research combines all these factors to experimentally realise a large-scale plasma-based amplifier, which can impact the high-energy laser industry in the near future.

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MAINFRAY, G. "RELATIVISTIC SELF-FOCUSING OF AN ULTRA-INTENSE LASER PULSE IN A PLASMA." Journal of Nonlinear Optical Physics & Materials 04, no. 03 (July 1995): 547–66. http://dx.doi.org/10.1142/s0218863595000239.

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New compact multiterawatt lasers allow us to study the relativistic regime of laserplasma interaction. The propagation of a multiterawatt subpicosecond laser pulse in a plasma has been investigated theoretically and experimentally. A 10 TW laser pulse at a 1064 nm wavelength has been focused in a hydrogen gas jet. Thomson scattering observations show that a relativistic self-focusing and channeling occur when the laser power exceeds a critical value predicted by theory. The amount of enhancement in self-focused intensity exceeds one order of magnitude. The laser pulse propagates through the plasma over a distance much larger than the Rayleigh length determined by vacuum diffraction.

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32

Michaelis, M. M., P. F. Cunningham, R. S. Cazalet, J. A. Waltham, and M. Notcutt. "Gas lens applications." Laser and Particle Beams 9, no. 2 (June 1991): 641–51. http://dx.doi.org/10.1017/s0263034600003645.

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Various gas lenses are briefly reviewed, together with their imperfections. We discuss the applicability of these lenses as objectives for telescopes and as the final focusing element of high-power laser systems: cw lasers in industry and pulsed lasers for plasma research. A novel phase conjugate experiment employing a gas lens is described. Pulsed gas lenses are proposed as a solution to the problems of high laser fluence and radiation damage in post-break-even fusion experiments.

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Bintanjoyo, Lunardi, and Diah Mira Indramaya. "Application of Picosecond Laser in Dermatology." Berkala Ilmu Kesehatan Kulit dan Kelamin 35, no. 2 (July 31, 2023): 158–62. http://dx.doi.org/10.20473/bikk.v35.2.2023.158-162.

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ABSTRACT Background: Lasers are one of the most important treatment modalities in dermatology. Lasers interact with chromophores through several mechanisms that depend on fluence and pulse durations. Early lasers worked by photothermal interaction with pulse durations of 1 microsecond to 1 second. A picosecond laser is developed to confine photothermal effects and produce photomechanical effects and plasma induction. Purpose: To understand the mechanism of action and application of picosecond lasers for dermatological disorders. Review: Non-fractional picosecond lasers work by photomechanical interaction. Photomechanical interaction happens when pulse duration is less than inertial confinement time, causing fractures of chromophores with lower energy, or “cold ablation”. Fractional picosecond lasers work by laser-induced optical breakdown (LIOB). In LIOB, accelerated seed electrons cause an electron avalanche that produce a collection of free electrons called plasma, which ablates tissues. LIOB in the skin is always followed by photodisruption. In LIOB, vacuoles and debris were eliminated transdermally and dermal collagen and elastin increased. Picosecond laser may be applied in disorders requiring destruction of chromophores and for collagen and elastin disorders. It is currently the first-line treatment for tattoo removal (Nevus of Ota and Acquired Bilateral Nevus of Ota-like macules, or ABNOM). It has good efficacy and safety for solar lentigines, freckles, and cafe-au-lait macules (CALM). It is an additional treatment for moderate to severe melasma and hypertrophic scars, in combination with other treatments. The fractional picosecond laser showed moderate improvement and low risk of postinflammatory hyperpigmentation (PIH) for atrophic acne scars and produced improvement in striae alba.

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Alekseev, N. N., A. N. Balabaev, A. A. Vasilyev, Yu A. Satov, S. M. Savin, B. Yu Sharkov, A. V. Shumshurov, and V. C. Roerich. "Development of laser-plasma generator for injector of C4+ ions." Laser and Particle Beams 30, no. 1 (January 19, 2012): 65–73. http://dx.doi.org/10.1017/s0263034611000693.

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AbstractThe results of the development of the ITEP accelerator carbon ion injector based on a repetition-rate CO2 laser ion source are described. The improvement includes a modified pulsed HV-feeding generator for the discharge formation in the laser gas mixture. The advanced discharge module ensures essential increase of the laser active volume and specific electrical deposition energy. The comparative computer simulations of the discharge characteristics for the improved and the prototype lasers are applied. The design and the output spatial-temporal parameters of the free-running laser “Malish-M” are shown, so the significant increase of the laser power is reached. The spatial characteristics of the laser beam obtained with diffraction calculations are compared to measured radial distribution of the energy density. The target laser intensity and the different channels of the energy loss of the laser beam in the optical scheme are estimated. Finally, the output C4+ current trace of heavy ion injector as well as the injector scheme are shown.

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35

Kumar, Sonu, Dhananjay K. Singh, and Hitendra K. Malik. "Comparative study of ultrashort single-pulse and multi-pulse driven laser wakefield acceleration." Laser Physics Letters 20, no. 2 (December 30, 2022): 026001. http://dx.doi.org/10.1088/1612-202x/aca978.

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Abstract Laser wakefield acceleration (LWFA) is a promising technique to build compact and powerful particle accelerators. In such accelerators, the electric fields required to accelerate charged particles are sustained by electron density modulations in the plasma. The plasma wave modulating the electron density may be excited by an intense laser pulse. However, propagation of intense laser pulse in plasma is subject to various instabilities which result in significant losses of laser energy, reducing the efficiency of wakefield generation. Using a train of lower intensity pulses instead of a single higher intensity pulse appears to be a more efficient scheme for LWFA. Here we have studied this alternative scheme by applying an ultra-short femtosecond Gaussian laser beam consisting pulse train of a various number of pulses in different cases to underdense plasma. The plasma density modulation and strength of the resulting wakefield have been compared in various cases of multi-pulse and single-pulse lasers, for the same amount of input energies. Here we demonstrate that applying multi-laser pulses of optimally selected lower intensities and proper spacing leads to stronger wakefield generation and more efficient electron acceleration compared to the case of a single pulse of higher energy.

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36

Mao, X. L., A. C. Ciocan, and R. E. Russo. "Preferential Vaporization during Laser Ablation Inductively Coupled Plasma Atomic Emission Spectroscopy." Applied Spectroscopy 52, no. 7 (July 1998): 913–18. http://dx.doi.org/10.1366/0003702981944706.

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The Zn-to-Cu ratio in brass was measured by laser ablation inductively coupled plasma atomic emission spectroscopy. The influence of laser beam properties (pulse width, wavelength, and power density) on fractional laser ablation was investigated. The behavior of the Zn/Cu ratio vs. laser power density shows that there are different mechanisms influencing ps and ns laser ablation. With the use of a 30 ns pulse duration from an excimer laser, thermal vaporization appears to be the dominant process in the low-power density region. The Zn/Cu ratio approaches stoichiometry at higher power density, but the ablated mass still remains Zn rich. With a 35 ps pulse Nd:YAG laser, a nonthermal mechanism appears to govern the laser ablation process. When a 3 ns Nd:YAG laser is used, both thermal and nonthermal processes exist. For both 3 ns and 30 ps Nd:YAG lasers, stoichiometric ablation can be achieved at higher power densities.

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37

Renner, O., L. Juha, J. Krasa, E. Krousky, M. Pfeifer, A. Velyhan, C. Granja, et al. "Low-energy nuclear transitions in subrelativistic laser-generated plasmas." Laser and Particle Beams 26, no. 2 (June 2008): 249–57. http://dx.doi.org/10.1017/s0263034608000293.

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AbstractThe aim of the reported research is to contribute to investigation of new processes and methods interlinking nuclear and laser-plasma physics. With respect to requirements of nuclear experiments at medium-size high-power lasers, the selection of proper candidates for studying the excitation and decay of low-lying nuclear states is reviewed. An experimental approach to the identification of low-energy nuclear transitions is discussed, simple estimates of the 181Ta excitation yield in the laser-generated plasma provide a theoretical basis for planning future work. First tests and results of the experiments at the laser facility PALS are presented.

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38

Lipova, E., M. Rakhmatulina, I. Glazko, and A. Chekmarev. "Laser and Radiowave Technologies in Dermatovenerology and Cosmetology." Medical Radiology and radiation safety 65, no. 5 (April 25, 2021): 68–76. http://dx.doi.org/10.12737/1024-6177-2020-65-5-68-76.

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The article presents current data on the use of laser and radio-wave techniques in dermatology and cosmetology. Types of lasers, reactions of interaction of laser light with skin are characterized, the detailed characteristic of low-intensity and high-intensity laser radiation and opportunities of their application in dermatology and cosmetology is given. Ablative and non-ablative methods of skin exposure, the principle of fractional laser photothermolysis are described. The method of radiowave influence on tissues and its modes is presented. The principles of radiowave surgery and the possibility of using radiowave techniques in the treatment of skin tumors and aesthetic cosmetology are discussed. The data on the use of Plasma RFL regime for plasma skin rejuvenation are described.

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Asif, M., U. Amin, Z. U. Rehman, R. Ali, and H. Qayyum. "Characterization of the palladium plasma produced by nanosecond pulsed 532 nm and 1064 nm wavelength lasers." Laser Physics 32, no. 2 (December 24, 2021): 026002. http://dx.doi.org/10.1088/1555-6611/ac42d4.

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Abstract Palladium plasma produced by nanosecond pulsed 532 nm and 1064 nm wavelengths lasers is studied with the help of planer Langmuir probe. The experiment is conducted over a wide range of the laser fluence (1.6–40 J cm−2). The measured time of flight ions distributions are used to infer total charge, kinetic energy of the palladium ions and plasma parameters. Our results indicate that the ion charge produced by both laser wavelengths is an increasing function of the laser fluence. Initially, the ion charge produced by 1064 nm is lower than 532 nm, but it increases at much faster rate with the rise of laser fluence as the inverse bremsstrahlung plasma heating prevails at higher plasma densities. The most probable kinetic energy of the Pd ions produced by 1064 nm wavelength is also lower than that of 532 nm. The time varying plasma electron temperature and electron density are derived from the current–voltage plots of the two plasmas. For both wavelengths, the electron temperature and electron density rapidly climb to a maximum value and then gradually decline with time. However, in case of the 532 nm, the electron temperature and electron density remain consistently high throughout the laser plasma. The results are compared the available literature and discussed by considering surface reflectivity, ablation rate of the Pd target and laser plasma heating. The results presented in this work will provide more insight into the process of laser ablation and can be useful for the development of laser-plasma ion sources.

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40

Kazuhisa Nakajima, Kazuhisa Nakajima, Haiyang Lu Haiyang Lu, Xueyan Zhao Xueyan Zhao, Baifei Shen Baifei Shen, Ruxin Li Ruxin Li, and Zhizhan Xu Zhizhan Xu. "100-GeV large scale laser plasma electron acceleration by a multi-PW laser." Chinese Optics Letters 11, no. 1 (2013): 013501–13515. http://dx.doi.org/10.3788/col201311.013501.

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41

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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42

Zhou, Hong, Fei Li, Jun Wang, and Bao De Sun. "Microstructural Characterization of Thermal Barrier Coatings Glazed by a High Power Laser." Key Engineering Materials 723 (December 2016): 247–51. http://dx.doi.org/10.4028/www.scientific.net/kem.723.247.

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Thermal barrier coatings have been widely used in in both energy and propulsion systems. Plasma-sprayed thermal barrier coatings have relatively high interconnected porosity and lamina structure, which bring out a low bond strength, and lead to a short thermal cycling life. Lasers can be used for modification of materials surface. In this paper, plasma-sprayed thermal barrier coatings were laser-glazed by a high power laser in order to modify the structures. The microstructure of laser-glazed TBCs is investigated. The change on surface roughness has been examined. The result indicates that a smooth and dense glazed surface with craters and a network of microcracks is obtained after laser-glazing. The laser-glazed region consists of a columnar microstructure. There are segmentation microcracks in the laser-glazed coatings, which don’t run through the coatings along thickness. Surface roughness has been reduced significantly for the laser treated ceramic coatings.

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Weaver, J. L., J. Oh, B. Afeyan, L. Phillips, J. Seely, U. Feldman, C. Brown, et al. "Laser plasma instability experiments with KrF lasers." Physics of Plasmas 14, no. 5 (May 2007): 056316. http://dx.doi.org/10.1063/1.2672029.

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44

Nagli, L., and Y. Raichlin. "Polarization of the laser induced plasma lasers." Optics Communications 447 (September 2019): 51–54. http://dx.doi.org/10.1016/j.optcom.2019.04.090.

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45

Sharma, Prerana. "Cross Focusing of two Coaxial Gaussian Beams with Relativistic and Ponderomotive Nonlinearity." Zeitschrift für Naturforschung A 67, no. 1-2 (February 1, 2012): 10–14. http://dx.doi.org/10.5560/zna.2011-0064.

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This paper presents the cross focusing of two high power lasers by taking off-axial contributions of the laser beams in a collisionless plasma. Due to relativistic and ponderomotive nonlinearities the two laser beams affect the dynamics of each other and cross focusing takes place. The expressions for the laser beam intensities by using the eikonal method are derived. The contributions of the r2 and r4 terms are incorporated. By expanding the eikonal and the other relevant quantities up to the fourth power of r, the solution of the pump laser beam is obtained within the extended paraxial ray approximation. Filamentary structures of the laser beams are observed due to the relativistic and the ponderomotive nonlinearity. The focusing of the laser beams is shown to become fast in the extended paraxial region. Using the laser beam and the plasma parameters, appropriate for beat wave processes, the filaments of the laser beams are studied and the relevance of these results to beat wave processes is pointed out.

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Lan, Hui, Xinbing Wang, Hong Chen, Duluo Zuo, and Peixiang Lu. "Temporal evolution of Nd:YAG laser-produced Sn plasma." Chinese Optics Letters 13, Suppl. (2015): S21413. http://dx.doi.org/10.3788/col201513.s21413.

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47

Varshney, P., V. Sajal, A. Upadhyay, J. A. Chakera, and R. Kumar. "Tunable terahertz radiation generation by nonlinear photomixing of cosh-Gaussian laser pulses in corrugated magnetized plasma." Laser and Particle Beams 35, no. 2 (March 13, 2017): 279–85. http://dx.doi.org/10.1017/s0263034617000167.

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AbstractThis paper presents a scheme of THz generation by nonlinear photomixing of two cosh-Gaussian lasers pulses having different frequencies (ω1, ω2) and wave numbers $(\vec k_1, \vec k_2 )$ and same electrical field amplitude in a corrugated plasma embedded with transverse static magnetic field. Cosh-Gaussian laser pulses have steep gradient in intensity profile along with wider cross-section, which exerts a stronger nonlinear ponderomotive force at ω1 − ω2 and $\vec k_1 - \vec k_2 $ on plasma electrons imparting a nonlinear oscillatory velocity to plasma electrons. Oscillatory plasma electrons couple with the density ripple n′ = nα0eiαx to produce a nonlinear current, which is responsible for resonant THz radiation at frequency $\sim\left( {{\rm \omega} _{\rm c}^2 + {\rm \omega} _{\rm p}^2} \right)^{1/2} $. The amplitude, efficiency and beam quality of THz radiation can be optimized by choosing proper corrugation factor (α of the plasma), applied magnetic field (ωc), decentered parameter (b), and beam width parameter a0 of cosh-Gaussian lasers. An efficiency of $\sim\!10^{ - 2} - 10^{ - 1} $ is achieved for laser electric field E = 3.2 × 109 V/cm.

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Kiani, Leily, Tong Zhou, Seung-Whan Bahk, Jake Bromage, David Bruhwiler, E. Michael Campbell, Zenghu Chang, et al. "High average power ultrafast laser technologies for driving future advanced accelerators." Journal of Instrumentation 18, no. 08 (August 1, 2023): T08006. http://dx.doi.org/10.1088/1748-0221/18/08/t08006.

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Abstract Large scale laser facilities are needed to advance the energy frontier in high energy physics and accelerator physics. Laser plasma accelerators are core to advanced accelerator concepts aimed at reaching TeV electron electron colliders. In these facilities, intense laser pulses drive plasmas and are used to accelerate electrons to high energies in remarkably short distances. A laser plasma accelerator could in principle reach high energies with an accelerating length that is 1000 times shorter than in conventional RF based accelerators. Notionally, laser driven particle beam energies could scale beyond state of the art conventional accelerators. LPAs have produced multi GeV electron beams in about 20 cm with relative energy spread of about 2 percent, supported by highly developed laser technology. This validates key elements of the US DOE strategy for such accelerators to enable future colliders but extending best results to date to a TeV collider will require lasers with higher average power. While the per pulse energies envisioned for laser driven colliders are achievable with current lasers, low laser repetition rates limit potential collider luminosity. Applications will require rates of kHz to tens of kHz at Joules of energy and high efficiency, and a collider would require about 100 such stages, a leap from current Hz class LPAs. This represents a challenging 1000 fold increase in laser repetition rates beyond current state of the art. This whitepaper describes current research and outlook for candidate laser systems as well as the accompanying broadband and high damage threshold optics needed for driving future advanced accelerators.

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Nam, C. H., W. Tighe, S. Suckewer, U. Feldman, and J. Seely. "Generation of XUV Spectra by Powerful Picosecond Laser." International Astronomical Union Colloquium 102 (1988): 203–6. http://dx.doi.org/10.1017/s0252921100107705.

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AbstractThe development of laser action at wavelengths shorter than those of current X-ray lasers is being investigated along two fronts. In the first case, we are exploring the possibilities for laser action at 15.4 nm in Li-like AIXI and 12.9 nm in Li-like SiXII in a magnetically confined recombining plasma. Previous work on hydrogen-like carbon, CVI, led to lasing action at 18.2 nm. Recently, this has been applied to microscopy and first results from a soft X-ray laser microscope are presented. A new technique to generate shorter wavelength X-ray lasing involves the interaction of a high power laser with a preformed plasma. The Powerful Picosecond Laser (PP-Laser) System with an output power level of 20-30 GW and focussed power density of 1016- 1017W/cm2has recently become operational. The spectra of highly ionized atoms in the XUV region were recorded on a high resolution grazing incidence spectrometer for the PP-Laser beam interacting with different solid targets.

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Singh, Dheeraj K., B. Dikshit, R. Vijayan, Jaya Mukherjee, and V. S. Rawat. "Analysis of the discharge plasma impedance of copper vapor laser." Laser Physics 32, no. 5 (April 28, 2022): 055002. http://dx.doi.org/10.1088/1555-6611/ac603b.

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Abstract In the pursuit to analyze the impedance of copper vapor lasers (CVLs) in different conditions, a novel approach has been proposed in this paper. The underdamped behavior of the voltage waveform across the CVL is leveraged to compute the impedance of high-voltage discharge plasma in the laser. This methodology provides an accurate idea of the discharge plasma resistance and inductance as it is calculated on the basis of experimental voltage waveforms obtained from the laser system. The laser head inductance remains almost fixed and equivalent to ∼0.47 µH whereas the laser resistance changes between 34 Ω and 11 Ω depending on the discharge condition and its constituents. A critical evaluation of CVL impedance is done in all experimentally possible conditions, and a methodology has been proposed to maintain the CVL impedance, which results in the power stability of the laser in oscillator–amplifier configuration. The laser impedance variation w.r.t. time, pressure, operating voltage and electrode pin configuration has been investigated. The impact of the localized electric field at the electrode on the laser resistance has also been emphasized in this paper. A good concurrence exists between the calculated laser impedance and its experimental behavior.

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Journal articles on the topic 'Laser plaama'

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