共振混频过程的超快弛豫现象研究

Study of ultrafast relaxation phenomena based on resonant optical mixing process

本文报导利用共振混频过程,可在不利用超短脉冲激光情况下对皮秒甚至飞秒量级的超快弛豫进行测量。采用密度矩阵方法对该混频过程的二能级系统的非线性极化率X_R进行了计算,结果表明过程的频率特性与样品的纵向弛豫时间T_1和横向弛豫时间T_2有关。实验测量得到孔雀绿水溶液的T_1和T_2分别为1.20ps和0.09ps。

The measurement of ultrafast relaxation phenomena on the order of picoseconds or femtoseconds using the techniques based on resonant optical miixng process without ultrashort light pulses has been reported in this paper. By means of density-matrix method, we calculated the nonlinear polarzability X_R(3) for this resonant mixing process generated in a two-level system. The results show that the frequency characteristic in this paper depends on longitudinal (T_1) and transverse (T_2) relaxation times. The T_1 and T_2, relaxation times of Malachite Green in water have been also reported. Their values are 1.20 ps and 0.09 ps respectively.