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近红外光谱仪是重要的光学分析仪器,具有重要的应用价值。为了实现近红外波段高动态、可调谐分辨率光谱的探测,设置入射狭缝、中间狭缝和出射狭缝,构建了基于准Littrow结构的单光栅双路光谱仪,并利用Zemax软件进行光学系统仿真。在此基础上,研制了实验室用近红外光谱仪,包括光机模块、控制分析模块和探测模块,系统的工作波长为600~1700nm。结果表明:光束以准Littrow角2次经过平面光栅,能有效消除出射光斑的空间色散效应,减小出射光斑的几何尺寸,进而有效抑制光谱信号的边模噪声和降低杂散光强度;光路系统配合自主研制的高动态光电探测系统扩大了获取光谱信号的动态范围;经过光谱标定和相对辐射标定后,利用构建系统对窄带宽激光光源进行探测,系统最高的光谱分辨率(即半峰全宽)优于0.05nm,测得复原激光光谱在中心波长±1nm范围内的动态范围优于70dB。
Near infrared spectrometer is an important optical analysis instrument, has important application value. In order to realize the detection of highly dynamic and tunable resolution spectrum in the near infrared band, the entrance slit, the middle slit and the exit slit were set up. A single grating double spectrometer based on the quasi-Littrow structure was constructed and the optical system simulation was performed by Zemax software . On this basis, a near infrared spectrometer for laboratory was developed, including optical module, control analysis module and detection module. The operating wavelength of the system is 600 ~ 1700nm. The results show that the light beam passes the plane grating twice with the quasi-Littrow angle, which can effectively eliminate the spatial dispersion effect of the exit spot and reduce the geometrical size of the exit spot, thereby effectively suppressing the side mode noise of the spectral signal and reducing the stray light intensity. The self-developed high-dynamic photodetection system expands the dynamic range of obtaining the spectrum signal. After the calibration of the spectrum and the relative radiation calibration, the narrowband laser light source is detected by the construction system. The highest spectral resolution (ie, the full width at half maximum) Better than 0.05 nm, the measured dynamic range of the reconstituted laser spectrum over the central wavelength ± 1 nm is better than 70 dB.