纵向非均匀等离子体介质中厄密高斯光束的线性传输研究
摘要：本文主要研究厄密高斯光束在等离子体介质中的线性傍轴传输特性。主要包括如下内容：从麦克斯韦方程和冷单流体(电子)模型出发，推导出等离子体介质中包含等离子体密度纵向不均匀效应的激光束线性传输方程；在傍轴近似和缓变包络近似下，利用傅立叶变换方法，得出传输方程衍射积分形式的通解。该通解可以用来分析任意形式纵向密度不均匀等离子体对光束传输特性的影响。利用该通解，对厄密高斯光束总功率和桶中功率随传输距离演化进行了分析，结果表明等离子体密度纵向不均匀性将导致光束功率的增长。同时，线性的纵向等离子体密度不均匀性比2次型的对光束功率的影响更大。
关键词：厄密高斯光束；等离子体；传输特性；解析解
Study on the linear propagation of Hermite-Gauss beam in longitudinal inhomogeneous plasmas
Abstract: In this paper, the linear paraxial propagation properties of Hermite-Gauss beam in longitudinal inhomogeneous plasmas in studied. From the Maxwell’s equations and the cold fluid (electron) equation, we derive the linear propagation equation for laser beam field. Making use of the paraxial approximation and the slowly-varying envelope approximation, a linear paraxial equation modified by longitudinal inhomogeneous plasma is obtained, from which, we derive a general solution in the form of diffraction-integral for the beam field using the Fourier transform technique. This general solution can used to analyze the beam propagation properties in all kinds of longitudinal inhomogeneous plasmas as long as the initial form of the beam is given. And the total power and the power in barrel (PIB) of the beam with initial Hermite-Gauss form is analyzed. It is found that longitudinal inhomogeneous density enhances the powers.
Key words: Hermite-Gauss beam; plasma; propagation properties; analytic solution
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