Nag Amit, Goswami Debabrata
Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh - 208016, India.
J Spectrosc Dyn. 2012 Aug 31;2(3).
Coherent control via linear chirping a femtosecond laser pulse holds the promise of a potent spectroscopic tool in the study of two-photon processes in condensed phase. Here, we show modulation in the two-photon absorption and fluorescence of several common dyes in solution by simple phase ordering of femtosecond laser pulse into a linearly frequency chirped pulse. However, the modulation is dependent on associated solvent properties as the coherence is lost rapidly in the solution phase. Also, systematic effects are mostly seen only over a limited range of chirp since it is an interplay of two opposing effects on two-photon processes-linear chirp enhancing it while the associated pulse broadening reducing it.
通过对飞秒激光脉冲进行线性啁啾实现的相干控制，有望成为研究凝聚相中双光子过程的强大光谱工具。在此，我们展示了通过将飞秒激光脉冲简单地相位排序为线性频率啁啾脉冲，来调制溶液中几种常见染料的双光子吸收和荧光。然而，这种调制依赖于相关的溶剂性质，因为相干性在溶液相中会迅速丧失。此外，由于这是两种对双光子过程起相反作用的效应之间的相互作用——线性啁啾增强双光子过程，而相关的脉冲展宽则削弱双光子过程，所以系统效应大多仅在有限的啁啾范围内可见。
