Talukder M A, Amagishi Y, Tomita M
Department of Physics, Faculty of Science, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan.
Phys Rev Lett. 2001 Apr 16;86(16):3546-9. doi: 10.1103/PhysRevLett.86.3546.
We have examined the propagation of femtosecond laser pulses in an absorbing dye solution through a short to a long range of propagation distance. The transmitted pulses show strong spectral shift and a superluminal to subluminal transition in the propagation velocity keeping its initial shape almost intact. It is verified that the peak velocity is well described by a modified group velocity v(S) defined within the framework of the saddle-point method as well as by a recent prediction of the net group delay of surviving frequency.
我们研究了飞秒激光脉冲在吸收性染料溶液中的传播，传播距离从短到长。透射脉冲呈现出强烈的光谱频移以及传播速度从超光速到亚光速的转变，且脉冲初始形状几乎保持不变。结果证实，峰值速度可以通过在鞍点法框架内定义的修正群速度v(S)以及最近关于幸存频率净群延迟的预测得到很好的描述。
