Konar Arkaprabha, Lozovoy Vadim V, Dantus Marcos
Department of Chemistry and ‡Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States.
J Phys Chem A. 2016 Mar 31;120(12):2002-8. doi: 10.1021/acs.jpca.6b02010. Epub 2016 Mar 21.
Controlling stimulated emission is of importance because it competes with absorption and fluorescence under intense laser excitation. We performed resonant nonlinear optical spectroscopy measurements using femtosecond pulses shaped by π- or π/2-step phase functions and carried out calculations based on density matrix representation to elucidate the experimental results. In addition, we compared enhancements obtained when using other pulse shaping functions (chirp, third-order dispersion, and a time-delayed probe). The light transmitted through the high optical density solution was dominated by an intense stimulated emission feature that was 14 times greater for shaped pulses than for transform limited pulses. Coherent enhancement depending on the frequency, temporal, and phase characteristics of the shaped pulse is responsible for the experimental observations.
控制受激辐射很重要，因为在强激光激发下它会与吸收和荧光相互竞争。我们使用由π或π/2步长相位函数整形的飞秒脉冲进行了共振非线性光学光谱测量，并基于密度矩阵表示进行了计算以阐明实验结果。此外，我们比较了使用其他脉冲整形函数（啁啾、三阶色散和延时探测）时获得的增强效果。透过高光密度溶液的光主要由强烈的受激辐射特征主导，整形脉冲的该特征比变换极限脉冲大14倍。取决于整形脉冲的频率、时间和相位特性的相干增强是实验观测结果的原因。
