发表机构
Texas A&M University（德州农工大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究利用涨落-耗散定理分析激光驱动密度光栅的受激光散射，将其融入动力学框架简化分析，推导出受激增益的闭式解，能恢复流体动力学中声波介导的斯托克斯放大特性。
AI 中文摘要
涨落-耗散定理（FDT）被证明是分析激光驱动密度光栅受激光散射的有力工具，包括受激布里渊散射及其动力学 regime 扩展。在密度光栅受激光散射的物理环境中，FDT 表明激光驱动电致伸缩力在介质中引起的扰动动力学与平衡时介质内部自发涨落的动力学遵循相同物理路径。当集成到合适的动力学框架中时，FDT 可显著简化受激光散射的分析，无需求解带有外场项的动力学方程即可直接从自发密度涨落谱中找到受激增益/损耗谱。在此框架内，我们推导出了受激增益的物理直观闭式解，该解能准确恢复流体动力学 regime 中声波介导的斯托克斯放大的所有特征特性，提供从流体动力学到受激散射动力学 regime 的连续、完全解析的交叉，并解释了密度光栅动力学受激散射的明显不同特性，与中压气体中受激散射的实验结果一致。作为重要的物理基准，在极低和极高碰撞频率的极限下，该 SBS 增益解分别恢复了 Vlasov 和 Navier - Stokes 方程的 FDT 变换解。
英文摘要
The fluctuation - dissipation theorem (FDT) is shown to provide a powerful resource for the analysis of stimulated light scattering from laser-driven density gratings, including stimulated Brillouin scattering (SBS) and its kinetic-regime extension. In the physical setting of stimulated light scattering by density gratings, the FDT establishes that the dynamics of disturbances induced in a medium by a laser-driven electrostrictive force unfolds via the same physical pathways as the dynamics of internal, spontaneous fluctuations in this medium at equilibrium. When integrated into a suitable kinetic framework, the FDT leads to a significant simplification of the analysis of stimulated light scattering, allowing the stimulated gain/loss spectrum to be found directly from the spectrum of spontaneous density fluctuations without the need to solve kinetic equations with an external-field term. Such FDT-based framework enables an accurate description of stimulated light scattering within a vast parameter space, recovering all the signature properties of sound-wave-mediated Stokes amplification in the hydrodynamic regime, providing a continuous crossover from the hydrodynamic to kinetic regime of stimulated scattering, and explaining distinctly different properties of kinetic stimulated scattering from density gratings, consistent with experiments on stimulated scattering in moderate-pressure gases. As important physical benchmarks, in the limits of vanishingly low and very high collision frequencies, this solution for the SBS gain recovers the FDT-transformed solutions of, respectively, the Vlasov and Navier - Stokes equations.
