采用钛宝石飞秒激光器输出的一部分光抽运光子晶体光纤以产生超连续光谱,作为抽运光和斯托克斯光,另一部分飞秒激光作为探测光,并结合时间延迟方法,建立超连续光谱激发时间分辨相干反斯托克斯拉曼散射(CARS)实验系统,测试了具有较宽拉曼光谱的二甲基亚砜样品.实验结果表明,所建立的实验系统能有效抑制非共振背景噪声,并且通过一次测量,即可获得二甲基亚砜在690—3200cm-1范围内的CARS光谱信息,获得的二甲基亚砜CARS光谱范围达到2500cm-1.同时给出了所采用的光子晶体光纤光谱展宽的实验结果.
In this paper,we present the development and experimental results of a time-resolved coherent anti-Stokes Raman scattering ( CARS) experiment setup that is based on supercontinuum excitation and precise time-delay control. The output of a Ti-sapphire femtosecond laser is divided into two parts. One part is used to pump a photonic crystal fiber (PCF) to generate supercontinuum spectrum which is used as pump and stokes beams. The other part of the femtosecond laser is used as the probe light. Dimethyl sulfoxid, a sample with broad range of Raman spectrum was tested. Experimental results show that this system can inhibit the non-resonant background noise effectively and obtain CARS spectrum of dimethyl sulfoxide in the frequency range of 690—3200 cm -1 in one measurement,which means that spectrum range of the acquired CARS spectrum of dimethyl sulfoxide is 2500 cm -1 . We also present experimental results of supercontinuum generation using a PCF.