Laser Linewidth and Spectral Resolution in Infrared Scanning Sum Frequency Generation Vibrational Spectroscopy System  

红外扫描和频振动光谱系统的激光线宽与光谱分辨率

作　　者：魏锋[1] 夏文秀[2] 胡中进 李雯慧[1] 张纪英[1] 郑万泉[1,3] 

机构地区：[1]江汉大学交叉学科研究院,光电化学材料与器件教育部重点实验室,武汉430056 [2]江汉大学生命科学学院,武汉430056 [3]巴黎第十一大学分子科学研究所,巴黎91405

出　　处：《Chinese Journal of Chemical Physics》2016年第2期171-178,I0001,共9页化学物理学报（英文）

摘　　要：Sum frequency generation vibrational spectroscopy （SFG-VS） is a robust technique for inter- facial investigation at molecular level. The performance of SFG-VS mostly depends on the spectral resolution of the SFG system. In this research, a simplified function was deduced to calculate the spectral resolution of picosecond SFG system and the lineshape of SFG spectra based on the Guassian shaped functions of IR beam and visible beam. The function indicates that the lineshpe of SFG spectra from nonresonant samples can be calculated by the Guassian widths of both IR beam and visible beam. And the Voigt lineshape of SFG spectra from vibrational resonant samples can be calculated by the Homogeneous broadening （Lorentzian width） and Inhomogeneous broadening （Guassian width） of vibrational modes, as well as the Guassian widths of both IR beam and visible beam. Such functions were also applied to verify the spectral resolution of the polarization-resolved and frequency-resolved picosecond SFG-VS system which was developed by our group recently. It is shown that the linewidths of IR beams that generated from current laser system are about 1.5 cm-1. The calculated spectral resolution of current picosecond IR scanning SFG-VS system is about 4.6 cm-1, which is consist with he spctral resolution shown in the spectra of cholesterol monolayer （3.5-5 cm-1）.

关 键 词：Lineshape calculation Sum frequency generation Vibrational spectra Spectralresolution 

分 类 号：O[理学]