Yampolsky N A, Malkin V M, Fisch N J
Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Mar;69(3 Pt 2):036401. doi: 10.1103/PhysRevE.69.036401. Epub 2004 Mar 11.
In the process of backward Raman amplification (BRA), the leading layers of the seed laser pulse can shadow the rear layers, thus weakening the effective seeding power and affecting parameters of output pulses in BRA. We study this effect numerically and also analytically by approximating the pumped pulse by the "pi-pulse" manifold (family) of self-similar solutions. We determine how the pumped pulse projection moves within the pi-pulse manifold, and describe quantitatively the effective seeding power evolution. Our results extend the quantitative theory of BRA to regimes where the effective seeding power varies substantially during the amplification. These results might be of broader interest, since the basic equations are general equations for resonant three-wave interactions.
在反向拉曼放大（BRA）过程中，种子激光脉冲的前沿会遮挡后沿，从而削弱有效种子功率，并影响BRA中输出脉冲的参数。我们通过用自相似解的“π脉冲”流形（族）近似泵浦脉冲，对这种效应进行了数值研究和解析研究。我们确定了泵浦脉冲投影在π脉冲流形内的移动方式，并定量描述了有效种子功率的演变。我们的结果将BRA的定量理论扩展到了有效种子功率在放大过程中大幅变化的情况。这些结果可能具有更广泛的意义，因为基本方程是共振三波相互作用的通用方程。
