共查询到20条相似文献,搜索用时 78 毫秒
1.
对激光惯性约束聚变(ICF)驱动器终端光学系统中连续相位板(CPP)的位置优化进行了研究.根据高强度激光非线性及微扰传输理论计算了CPP前置时激光通过频率转换系统以后的近远场光束特性和系统的三倍频转换效率.研究发现,前置于基频光路的CPP对三倍频转换效率和出射光束特性均有影响,但只要远场圆形焦斑直径小于05 mm,三倍频转换效率的下降与出射光束通量对比度的上升均在容许范围之内,同时远场焦斑形态和能量集中度也符合设计要求.对于实现远场小焦斑匀滑的CPP前置于ICF的基频光路中进行光束匀滑和整形,不会对IC
关键词:
连续相位板
束匀滑元件
惯性约束聚变
光束通量对比度 相似文献
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在惯性约束聚变驱动器终端光学系统中,束匀滑器件前置有许多优点,但它同时也将对频率转换系统的工作状态产生影响.从系统集成优化的观点研究了这种影响,并基于高强度激光非线性传输理论,采用耦合波方程组及微扰理论,模拟计算了连续相位板前置时基频光束通过频率转换系统的三倍频转换效率及出射光束的近远场分布和焦斑形态,提出了优化倍频晶体失谐角和晶体厚度以减小CPP前置对系统性能的影响.模拟计算了频率转换系统优化前后的三倍频转换效率、光束通量对比度和能量集中度,并进行了对比分析.分析结果表明,频率转换系统的优化对减小CPP
关键词:
惯性约束聚变
频率转换系统
连续相位板
系统集成优化 相似文献
3.
为降低高功率激光系统中连续相位板(CPP)后续元件的强激光损伤风险,综合考虑入射光强调制、干涉及衍射作用等多种影响因素,建立了CPP近场计算分析模型,模拟和分析了这些因素对CPP后的近场均匀性的影响。理论分析结果表明:CPP后的光束近场均匀性主要受入射光调制、CPP表面剩余反射率和衍射传输距离的影响;当入射光束质量较差时,CPP后的近场均匀性主要由入射光束质量决定,CPP剩余反射率和衍射传输距离对近场均匀性影响相对较小;但当光束质量比较理想时,干涉和衍射作用会破坏CPP的近场均匀性,衍射传输距离影响尤为突出。 相似文献
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为降低高功率激光系统中连续相位板(CPP)后续元件的强激光损伤风险,综合考虑入射光强调制、干涉及衍射作用等多种影响因素,建立了CPP近场计算分析模型,模拟和分析了这些因素对CPP后的近场均匀性的影响。理论分析结果表明:CPP后的光束近场均匀性主要受入射光调制、CPP表面剩余反射率和衍射传输距离的影响;当入射光束质量较差时,CPP后的近场均匀性主要由入射光束质量决定,CPP剩余反射率和衍射传输距离对近场均匀性影响相对较小;但当光束质量比较理想时,干涉和衍射作用会破坏CPP的近场均匀性,衍射传输距离影响尤为突出。 相似文献
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针对高功率激光装置对靶面辐照均匀性的需求,提出了一种基于宽带激光拍频的瞬时束匀滑技术。激光集束采用宽带激光,利用连续相位板对焦斑包络进行控制,并结合共轭螺旋相位板使得集束中各子束在焦平面处拍频产生旋转周期不同、位置各异的快速运动散斑。合理选择宽带光参数可使得散斑的旋转周期在皮秒至亚皮秒量级,从而达到瞬时匀滑焦斑的目的。通过建立基于宽带激光拍频的瞬时束匀滑技术物理模型,模拟分析了关键参数包括激光带宽和谱线类型对焦斑束匀滑特性的影响和规律,并与双频单色激光拍频技术作了比较分析。研究结果表明,通过合理选取光源谱线类型或增大激光带宽,所提技术可在降低系统要求的基础上增强对激光等离子体不稳定性的抑制,使焦斑实现瞬时匀滑并获得较好的均匀性。 相似文献
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高功率激光放大器中光束的成丝和B积分 总被引:9,自引:4,他引:9
研究了高功率激光放大器中光束的成丝问题,利用弗兰兹-诺德威克(Frantz-Nodvik)模型将准稳态波动议程推广到介质有饱和增益的情形,进而得到高功率激光放大器中小尺度调制的传输方程,在小信号增益和饱和增益情形下,分别得到了小尺度调制方程的精确解析解和数值解。结果表明,对于相同的输入光强,增益使小尺度调制增益谱的范围加宽,最快增长频率增高,最大增长率提高;同时,在放大介质中,小尺度调制的最快增长频率和最大增长率还随传输距离变化,增益饱和效应使小尺度调制的增长速度以及B积分的增长低于无饱和放大情形。 相似文献
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Sarri G Cecchetti CA Jung R Hobbs P James S Lockyear J Stevenson RM Doria D Hoarty DJ Willi O Borghesi M 《Physical review letters》2011,106(9):095001
The onset of filamentation, following the interaction of a relatively long (τ(L)?1 ns) and intense (I(L)?5×10(14) W/cm(2)) laser pulse with a neopentane filled gas bag target, has been experimentally studied via the proton radiography technique, in conditions of direct relevance to the indirect drive inertial confinement fusion scheme. The density gradients associated with filamentation onset have been spatially resolved yielding direct and unambiguous evidence of filament formation and quantitative information about the filamentation mechanism in agreement with previous theoretical modelings. Experimental data confirm that, once spatially smoothed laser beams are used, filamentation is not a relevant phenomenon during the heating laser beams propagation through typical hohlraum gas fills. 相似文献
13.
We investigate filamentation of a cw laser beam in soft matter such as colloidal suspensions and fractal gels. The process, driven by electrostriction, is strongly affected by material properties, which are taken into account via the static structure factor, and have impact on the statistics of the light filaments. 相似文献
14.
To simulate the intense bunched beam transport, a computer
program LEADS-3D has been developed. The particle trajectories are
analysed with the Lie algebraic method. The third order
approximation of the trajectory solutions is made with space charge
forces off, and the second order approximation is made with space
charge forces on. The particle distribution in the 3D ellipsoid is
uniform or Gaussian. Most of the conventional beam optical elements
are incorporated in the code. The optimization procedures are
provided to fit the beam lines to satisfy the given optical
conditions. 相似文献
15.
A new ray-tracing scheme is proposed to simulate the non-linear propagation of ultra-short pulses. The results are in good agreement with experimental data and numerical solving of the non-linear Schrödinger equation in both the self-focusing and the filamentation regions. In particular, they indicate a major contribution of the photon bath in the self-guided propagation of ultra-short pulses. The model suggests that a pure-Kerr self-guiding mode can allow filamentation without ionization. PACS 42.65.Jx; 42.15.Dp 相似文献
16.
Numerical analysis for smoothing of CW multimode beam transformed by time-varying random phase plate
The numerical analysis of CW multimode laser beam transformed by time-varying random phase plate is presented in this paper. The method is based on diffraction integral formula. The dependence of the intensity distribution on the element size, changing frequency and duty ratio is discussed in detail. The numerical results account for the experimental results satisfactorily. 相似文献
17.
Chunfu Huang 《Optik》2012,123(2):140-143
We investigate numerically the interactions of partially spatially incoherent odd dark solitons in a de-focusing kerr nonlinear media based on the coherent density approach, and find that a pair of partially spatially incoherent dark solitons may be changed from repulsion to attraction with an appropriate incoherence parameter. Moreover, a pair of partially incoherent gray soliton may form under appropriate conditions. Some numerical examples are provided to illustrate their interaction behavior further. 相似文献
18.
Froula DH Divol L Berger RL London RA Meezan NB Strozzi DJ Neumayer P Ross JS Stagnitto S Suter LJ Glenzer SH 《Physical review letters》2008,101(11):115002
We demonstrate a significant reduction of stimulated Brillouin scattering by polarization smoothing in large-scale high-temperature hohlraum plasma conditions where filamentation is measured to be negligible. The stimulated Brillouin scattering experimental threshold (defined as the intensity at which 5% of the incident light is backscattered) is measured to increase by a factor of 1.7+/-0.2 when polarization smoothing is applied. An analytical model relevant to inertial confinement fusion plasma conditions shows that the measured reduction in backscatter with polarization smoothing results from the random spatial variation in polarization of the laser beam, not from the reduction in beam contrast. 相似文献
19.
D.E. Roskey M. Kolesik J.V. Moloney E.M. Wright 《Applied physics. B, Lasers and optics》2007,86(2):249-258
We demonstrate through computer simulation that power partitioning due to linear diffraction can play a crucial role in the
break up of high intensity apertured beams propagating in air. By investigating the way linear diffraction partitions power
in these beams, we are able to predict the positions and relative powers of supercritical hot spots.
PACS 42.65.k; 42.65.Jx 相似文献
20.
B. V. Alekseev S. B. Karasev V. M. Krutilina G. V. Nesterov 《Russian Physics Journal》1981,24(10):974-977
Monte Carlo calculations have been carried out for the relaxation of electron beams in dense media. Calculations have been carried out for initial beam energies from 0.2 to 1 MeV and for targets of copper, tin, and air. The results on the energy dissipation are compared for the cases in which the incident electrons have a function energy distribution and a realistic energy distribution. Comparison reveals a satisfactory agreement with data reported by Spencer. The intensity function for the volume bremsstrahlung of the electron beam is calculated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 84–87, October, 1981. 相似文献