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Fourmaux S, Payeur S, Buffechoux S, Lassonde P, St-Pierre C, Martin F, Kieffer JC. Pedestal cleaning for high laser pulse contrast ratio with a 100 TW class laser system. OPTICS EXPRESS 2011; 19:8486-8497. [PMID: 21643098 DOI: 10.1364/oe.19.008486] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Laser matter interaction at relativistic intensities using 100 TW class laser systems or higher is becoming more and more widespread. One of the critical issues of such laser systems is to let the laser pulse interact at high intensity with the solid target and avoid any pre-plasma. Thus, a high Laser Pulse Contrast Ratio (LPCR) parameter is of prime importance. We present the LPCR characterization of a high repetition 100 TW class laser system. We demonstrate that the generated Amplified Spontaneous Emission (ASE) degrades the overall LPCR performance. We propose a simple way to clean the pulse after the first amplification stage by introducing a solid state saturable absorber which results in a LPCR improvement to better than 10(10) with only a 30% energy loss at a 10 Hz repetition rate. We finally correlated this cleaning method with experimental results.
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Affiliation(s)
- S Fourmaux
- INRS-EMT, Université du Québec, Varennes, Québec, Canada.
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Lu W, Nicoul M, Shymanovich U, Tarasevitch A, Zhou P, Sokolowski-Tinten K, von der Linde D, Masek M, Gibbon P, Teubner U. Optimized Kalpha x-ray flashes from femtosecond-laser-irradiated foils. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:026404. [PMID: 19792265 DOI: 10.1103/physreve.80.026404] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Indexed: 05/28/2023]
Abstract
We investigate the generation of ultrashort Kalpha pulses from plasmas produced by intense femtosecond p-polarized laser pulses on Copper and Titanium targets. Particular attention is given to the interplay between the angle of incidence of the laser beam on the target and a controlled prepulse. It is observed experimentally that the Kalpha yield can be optimized for correspondingly different prepulse and plasma scale-length conditions. For steep electron-density gradients, maximum yields can be achieved at larger angles. For somewhat expanded plasmas expected in the case of laser pulses with a relatively poor contrast, the Kalpha yield can be enhanced by using a near-normal-incidence geometry. For a certain scale-length range (between 0.1 and 1 times a laser wavelength) the optimized yield is scale-length independent. Physically this situation arises because of the strong dependence of collisionless absorption mechanisms-in particular resonance absorption-on the angle of incidence and the plasma scale length, giving scope to optimize absorption and hence the Kalpha yield. This qualitative description is supported by calculations based on the classical resonance absorption mechanism and by particle-in-cell simulations. Finally, the latter simulations also show that even for initially steep gradients, a rapid profile expansion occurs at oblique angles in which ions are pulled back toward the laser by hot electrons circulating at the front of the target. The corresponding enhancement in Kalpha yield under these conditions seen in the present experiment represents strong evidence for this suprathermal shelf formation effect.
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Affiliation(s)
- W Lu
- Institut für Experimentelle Physik, Universität Duisburg-Essen, D-47048 Duisburg, Germany
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Rassuchine J, d'Humières E, Baton SD, Guillou P, Koenig M, Chahid M, Perez F, Fuchs J, Audebert P, Kodama R, Nakatsutsumi M, Ozaki N, Batani D, Morace A, Redaelli R, Gremillet L, Rousseaux C, Dorchies F, Fourment C, Santos JJ, Adams J, Korgan G, Malekos S, Hansen SB, Shepherd R, Flippo K, Gaillard S, Sentoku Y, Cowan TE. Enhanced hot-electron localization and heating in high-contrast ultraintense laser irradiation of microcone targets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:036408. [PMID: 19392065 DOI: 10.1103/physreve.79.036408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 01/09/2009] [Indexed: 05/27/2023]
Abstract
We report experiments demonstrating enhanced coupling efficiencies of high-contrast laser irradiation to nanofabricated conical targets. Peak temperatures near 200 eV are observed with modest laser energy (10 J), revealing similar hot-electron localization and material heating to reduced mass targets (RMTs), despite having a significantly larger mass. Collisional particle-in-cell simulations attribute the enhancement to self-generated resistive (approximately 10 MG) magnetic fields forming within the curvature of the cone wall, which confine energetic electrons to heat a reduced volume at the tip. This represents a different electron confinement mechanism (magnetic, as opposed to electrostatic sheath confinement in RMTs) controllable by target shape.
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Affiliation(s)
- J Rassuchine
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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Rassuchine J, d'Humières E, Baton S, Fuchs J, Guillou P, Koenig M, Kodama R, Nakatsutsumi M, Norimatsu T, Batani D, Morace A, Redaelli R, Gremillet L, Rousseaux C, Dorchies F, Fourment C, Santos JJ, Adams J, Korgan G, Malekos S, Sentoku Y, Cowan TE. Enhanced energy localization and heating in high contrast ultra-intense laser produced plasmas via novel conical micro-target design. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/112/2/022050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Chen LM, Kando M, Xu MH, Li YT, Koga J, Chen M, Xu H, Yuan XH, Dong QL, Sheng ZM, Bulanov SV, Kato Y, Zhang J, Tajima T. Study of x-ray emission enhancement via a high-contrast femtosecond laser interacting with a solid foil. PHYSICAL REVIEW LETTERS 2008; 100:045004. [PMID: 18352290 DOI: 10.1103/physrevlett.100.045004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Indexed: 05/26/2023]
Abstract
We observed the increase of the conversion efficiency from laser energy to Kalpha x-ray energy (eta(K)) produced by a 60 fs frequency doubled high-contrast laser pulse focused on a Cu foil, compared to the case of the fundamental laser pulse. eta(K) shows a strong dependence on the nonlinearly modified rising edge of the laser pulse. It reaches a maximum for a 100 fs negatively modified pulse. The hot electron efficient heating leads to the enhancement of eta(K). This demonstrates that high-contrast lasers are an effective tool for optimizing eta(K), via increasing the hot electrons by vacuum heating.
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Affiliation(s)
- L M Chen
- Advanced Photon Research Center, Kansai Photon Science Institute, JAEA, Kyoto 619-0215, Japan
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Zhidkov A, Nemoto K, Nayuki T, Oishi Y, Fuji T. Giant electromagnetic vortex and MeV monoenergetic electrons generated by short laser pulses in underdense plasma near quarter critical density region. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:016401. [PMID: 17677573 DOI: 10.1103/physreve.76.016401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 02/06/2007] [Indexed: 05/16/2023]
Abstract
Very efficient generation of monoenergetic, about 1MeV , electrons from underdense plasma with its electron density close to the critical, when irradiated by an intense femtosecond laser pulse, is found via two dimensional particle-in-cell simulation. The stimulated Raman scattering of a laser pulse with frequency omega< or =2omega(pl max) gives rise to a giant electromagnetic vortex. In contrast to electron acceleration by the well-known laser pulse wake, injected plasma electrons are accelerated up to vortex ponderomotive potential forming a quite monoenergetic distribution. A relatively high charge of such an electron source makes very efficient generation of soft gamma rays with homega>300 keV .
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Affiliation(s)
- Alexei Zhidkov
- Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka-shi, Kanagawa-Ken 240-0196, Japan
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Muro M, Takatani Y. Optical rotatory-dispersion-type spatial light modulator and characteristics of the modulated light. APPLIED OPTICS 2005; 44:3992-9. [PMID: 16004045 DOI: 10.1364/ao.44.003992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Among known temporal-spatial light modulation methods, there is no realistic method that can precisely control a light pulse simultaneously in the temporal and spatial domains. By careful consideration of the symmetries and topological properties of electromagnetic waves, a novel spatial light modulator has been developed to create different far-field patterns for each wavelength of linearly polarized light composed of various wavelength components. The system consists of an optical rotatory dispersion device, which is like a Faraday rotator, and a spatial light modulator with parallel-alignment nematic liquid-crystal cells. Numerical simulation results show the effectiveness of this new spatial light modulation method.
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Affiliation(s)
- Mikio Muro
- Photon Technology Department, Technical Institute, Kawasaki Heavy Industries, Ltd., 1-1 Kawasaki-cho, Akashi City, 673-8666, Japan.
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Cai DF, Gu YQ, Zheng ZJ, Zhou WM, Yang XD, Jiao CY, Chen H, Wen TS, Chunyu ST. Double-peak emission of hot electrons generated by femtosecond laser interaction with solid targets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:066410. [PMID: 15697517 DOI: 10.1103/physreve.70.066410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2003] [Revised: 08/19/2004] [Indexed: 05/24/2023]
Abstract
Double-peak emission of hot electrons has been observed in the interaction of a 60-fs, 125-mJ, 800-nm, p-polarized laser pulse with Al targets. One peak in the specular direction is due to the reflected laser light, which excites a plasma wave to accelerate electrons. The other peak, which is more consistent with theories of Phys. Plasmas 6, 2855 (1999)] and Phys. Rev. Lett 82, 743 (1999)], is produced by the resonance absorption at approximately 15 degrees from the target normal.
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Affiliation(s)
- D F Cai
- Key Laboratory of Density Plasma Physics, Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
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Zhidkov A, Koga J, Sasaki A, Uesaka M. Radiation damping effects on the interaction of ultraintense laser pulses with an overdense plasma. PHYSICAL REVIEW LETTERS 2002; 88:185002. [PMID: 12005689 DOI: 10.1103/physrevlett.88.185002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2001] [Indexed: 05/23/2023]
Abstract
A strong effect of radiation damping on the interaction of an ultraintense laser pulse with an overdense plasma slab is found and studied via a relativistic particle-in-cell simulation including ionization. Hot electrons generated by the irradiation of a laser pulse with a radiance of I lambda(2)>10(22) W microm(2)/cm(2) and duration of 20 fs can convert more than 35% of the laser energy to radiation. This incoherent x-ray emission lasts for only the pulse duration and can be intense. The radiation efficiency is shown to increase nonlinearly with laser intensity. Similar to cyclotron radiation, the radiation damping may restrain the maximal energy of relativistic electrons in ultraintense-laser-produced plasmas.
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Affiliation(s)
- A Zhidkov
- Nuclear Engineering Research Laboratory, Graduate School of Engineering, The University of Tokyo, 22-2 Shirane-shirakata, Tokai, Naka, Ibaraki 319-1188, Japan
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