时间分辨相干反斯托克斯拉曼散射显微成像技术中光的干涉

摘要

时间分辨相干反斯托克斯拉曼散射显微成像技术中的泵浦光和探测光采用同一波长,可以很大程度上降低成像系统对光源的要求.采用振幅矢量叠加法理论上计算了波长相同的两束光经由物镜产生的双光束干涉,分析了产生的CARS信号强度波动的原因,并提出通过调整泵浦光与探测光的偏振方向相互垂直的方案消除干涉项,这样可以实现时间分辨CARS消除非共振背景的同时,保证产生的信号稳定.%If wavelength of the pump and probe beam are the same in time-resolved coherent anti-Stokes Raman scattering microscopy, the requirements for the light source can be largely reduced. However, when the pump and probe beam with the same wavelength pass through the objective, the two beams will interference with each other on the focal plane of the objective, leading to the CARS signal intensity fluctuate drastically. Via adjusting polarization direction of the pump and the probe beam perpendicular to each other, the interference term is zero and the dramatically changes of the signal strength will be eliminated. Adjusting the polarization direction of the pump and probe beam can guarantee eliminating the non-resonant background in time-resolved CARS and the stability of the signal simultaneously.