Experimental observation and suppression of transverse stimulated Brillouin scattering in large optical components

Murray, J. R.; Smith, James R.; Ehrlich, R. B.; Kyrazis, Demos T.; Thompson, C. E.; Weiland, Timothy L.; Wilcox, Russell

doi:10.1364/josab.6.002402

Cited by 92 publications

(40 citation statements)

References 19 publications

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“…[1][2][3][4][5][6][7] In laser-driven inertial confinement fusion (ICF) experiments in gas-filled hohlraums, SBS backscatter is one of the LPI of greatest concern, since the scattered light frequencies are nearly the same as the incident light frequency and thus large levels of SBS backscatter have the potential to damage laser optics and amplifiers. 8,9 At the National Ignition Facility, the laser beams are smoothed spatially through the use of random phase plates, 10 which break up the beam into a collection of laser speckles that in vacuum have width $1:2Fk 0 and length 2pF 2 k 0 , where k 0 is the wavelength of the laser light (351 nm) and F is the focal parameter. Because of diffraction, beam overlap, and the use of polarization smoothing, 11 the effective speckle size in gas-filled hohlraums is somewhat smaller than its vacuum values (F $ 6-8 vs. F ¼ 20 in vacuum).…”

Section: Introductionmentioning

confidence: 99%

Multi-dimensional dynamics of stimulated Brillouin scattering in a laser speckle: Ion acoustic wave bowing, breakup, and laser-seeded two-ion-wave decay

et al. 2016

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Two- and three-dimensional particle-in-cell simulations of stimulated Brillouin scattering (SBS) in laser speckle geometry have been analyzed to evaluate the relative importance of competing nonlinear processes in the evolution and saturation of SBS. It is found that ion-trapping-induced wavefront bowing and breakup of ion acoustic waves (IAW) and the associated side-loss of trapped ions dominate electron-trapping-induced IAW wavefront bowing and breakup, as well as the two-ion-wave decay instability over a range of ZTe/Ti conditions and incident laser intensities. In the simulations, the latter instability does not govern the nonlinear saturation of SBS; however, evidence of two-ion-wave decay is seen, appearing as a modulation of the ion acoustic wavefronts. This modulation is periodic in the laser polarization plane, anti-symmetric across the speckle axis, and of a wavenumber matching that of the incident laser pulse. A simple analytic model is provided for how spatial “imprinting” from a high frequency inhomogeneity (in this case, the density modulation from the laser) in an unstable system with continuum eigenmodes can selectively amplify modes with wavenumbers that match that of the inhomogeneity.

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Section: Introductionmentioning

confidence: 99%

Multi-dimensional dynamics of stimulated Brillouin scattering in a laser speckle: Ion acoustic wave bowing, breakup, and laser-seeded two-ion-wave decay

et al. 2016

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“…Observations of SBS leading to energy loss and subsequent damage are well documented [13][14][15] . Detailed measurements of the SBS threshold at 351 nm, including observed damage and validation of predictions for transient behavior, were carried out in large diameter optics on the NOVA laser [16] .…”

Section: Sbs Suppression Systemmentioning

confidence: 99%

Recent laser upgrades at Sandia’s Z-backlighter facility in order to accommodate new requirements for magnetized liner inertial fusion on the Z-machine

Schwarz

Rambo

Armstrong

et al. 2016

High Pow Laser Sci Eng

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The Z-backlighter laser facility primarily consists of two high energy, high-power laser systems. Z-Beamlet laser (ZBL) (Rambo et al., Appl. Opt. 44, 2421) is a multi-kJ-class, nanosecond laser operating at 1054 nm which is frequency doubled to 527 nm in order to provide x-ray backlighting of high energy density events on the Z-machine. Z-Petawatt (ZPW) (Schwarz et al., J. Phys.: Conf. Ser. 112, 032020 (2008)) is a petawatt-class system operating at 1054 nm delivering up to 500 J in 500 fs for backlighting and various short-pulse laser experiments (see also Figure 10 for a facility overview). With the development of the magnetized liner inertial fusion (MagLIF) concept on the Z-machine, the primary backlighting missions of ZBL and ZPW have been adjusted accordingly. As a result, we have focused our recent efforts on increasing the output energy of ZBL from 2 to 4 kJ at 527 nm by modifying the fiber front end to now include extra bandwidth (for stimulated Brillouin scattering suppression). The MagLIF concept requires a well-defined/behaved beam for interaction with the pressurized fuel. Hence we have made great efforts to implement an adaptive optics system on ZBL and have explored the use of phase plates. We are also exploring concepts to use ZPW as a backlighter for ZBL driven MagLIF experiments. Alternatively, ZPW could be used as an additional fusion fuel pre-heater or as a temporally flexible high energy pre-pulse. All of these concepts require the ability to operate the ZPW in a nanosecond long-pulse mode, in which the beam can co-propagate with ZBL. Some of the proposed modifications are complete and most of them are well on their way.

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“…Density variations modulate the index of refraction, and the varying index of refraction spatially scatters Stokes light. The high power laser creates the potential for transient longitudinal SBS processes and has previously been associated with damage processes in mirrors and windows [6][7][8][9] . It is necessary to study the transient longitudinal SBS in detail to improve performance of the high power system consists of many large optical components.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on damage phenomenon induced by transient stimulated brillouin scattering

Zi-Ming

Lü

Guan

et al. 2009

2009 Conference on Lasers &Amp; Electro Optics &Amp; The Pacific Rim Conference on Lasers and Electro-Optics

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Experimental observation and suppression of transverse stimulated Brillouin scattering in large optical components

Cited by 92 publications

References 19 publications

Multi-dimensional dynamics of stimulated Brillouin scattering in a laser speckle: Ion acoustic wave bowing, breakup, and laser-seeded two-ion-wave decay

Multi-dimensional dynamics of stimulated Brillouin scattering in a laser speckle: Ion acoustic wave bowing, breakup, and laser-seeded two-ion-wave decay

Recent laser upgrades at Sandia’s Z-backlighter facility in order to accommodate new requirements for magnetized liner inertial fusion on the Z-machine

Numerical study on damage phenomenon induced by transient stimulated brillouin scattering

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