利用OMA谱仪测量飞秒激光的谐波光谱
A Measurement of the femtosecond laser harmonic spectrum by OMA spectrometer

本文给出了利用光学多道分析（OMA）谱仪测量飞秒激光谐波光谱的一种方法。该方法是利用OMA谱仪（谱分辨0.1nm ）加CCD（1152？1242）相机探测设备，用消色差的相机镜头作为空间分辨，在固体靶前表面测量了激光的二次谐波（2？0）光谱。结果显示：在平行于靶面的方向和接近于法线方向分别观测到了2？0光谱，但在接近于法线方向的谐波光谱出现了精细结构，并得到2？0谐波谱的分裂间隔约为3.183 nm。分析认为，自生磁场的产生和作用是导致二次谐波光谱精细结构及谐波谱分裂的主要原因。
This paper presents a method of using optical multi-channel spectrometer analysis (OMA) to measure femtosecond laser harmonic spectrum. The OMA spectrometer (with 0.1 nm spectral resolution) with CCD camera (1152？1242 resolutions) is used in this method, and the achromatic camera lens is as spatial resolution, the laser second harmonic (2？0) spectrum is measured in front of the solid target surface. Results shown that 2 ？0 spectrum were observed in the direction paralleled to the target surface and in close to the normal direction respectively, but fine structure also appeared in close to the normal direction of the harmonic spectrum, and the splitting interval to get 2？0 harmonic spectrum is about 3.183 nm. Analysis thinks the emergence and roles of spontaneous magnetic field are the main reasons lead to the second harmonic spectral fine structure and the harmonic spectrum division.