基于光克尔门技术的超快时间分辨测量系统的优化

以SrTiO3晶体作为光克尔介质,建立了一套基于光克尔门技术的超快时间分辨测量系统.由于SrTiO3晶体在强光作用下产生光克尔效应时,同时会产生宽谱带的双光子激发荧光,因此我们一方面通过采用锁相放大探测技术从同频率的荧光背景中提取信号光,另一方面通过设计自动数据采集系统提高测量效率.为避免背景荧光以及泵浦光散射等噪声对光电倍增管的曝光而造成的探测器对信号光的非线性响应,我们通过增加SrTiO<,3>晶体与探测器之间的距离以及采用封闭信号光路来减少因此而造成的测量误差.以小于150 fs波长为800 nm的激光脉冲作为泵浦光,其倍频光作为信号光,采用该系统实验得到了约200 fs的时间分辨率.

Improvement of the Ultrafast Time-Resolved Measuring System Based on the Optical Kerr-Gate Technique

Using the SrTiO3 crystal as the optical Kerr medium,we constructe an ultrafast time-resolved measuring system based on the optical Kerr-gate technique. Under the intense light, the SrTiO3 crystal not only exhibits the optical Kerr effect, but also emits a wide spectrum of two-photon excited fluorescence. Consequently, we extract the signals from the background fluorescence with the same frequency using the lock-in amplification technique. As well, a specialized automatic data acquisition system is designed ...