一种改进型非交叉非对称C-T结构近红外微型光谱仪设计

Design of the improved micro near spectrometer based on non-cross asymmetric C-T structure

针对基于固定光栅和阵列探测器的常规微型近红外光谱仪成本高、光谱范围窄等问题,提出了一种基于集成扫描光栅微镜的双探测器微型近红外光谱仪。该系统采用自制的集成扫描光栅微镜作为核心分光部件,可同时实现扫描与分光功能,光学系统设计利用两个聚焦镜和两个InGaAs单管探测器的空间布局避免不同光路之间的相互干扰,可实现双通道同时、独立工作,此外双通道探测器前内置不同截止波长的带通滤色片消除光谱重叠。采用光线追迹法建立了理论模型计算光学系统的初始结构参数;利用ZEMAX完成了光学系统的优化设计并给出优化结构参数。测试结果表明,该仪器工作波长范围:800~2532 nm,分辨率:小于12 nm(800~1600 nm)、小于17 nm(1600~2532 nm),整体尺寸:145 mm×135 mm×75 mm,具有宽光谱、小体积、低成本等优势。

The conventional NIR spectrometers based on fixed grating and array detectors have disadvantages of high cost and narrow spectral range.To address these issues,the dual single detectors NIR micro spectrometers are proposed,which are based on integrated scanning grating micromirror.This system employs the integrated scanning grating micromirror as the core component,which can realize the scanning and diffraction simultaneously.The spatial layout of two focusing mirrors and dual In Ga As single detector are utilized to avoid the mutual interference between different optical paths in the optical system design.It can realize the simultaneous and independent operation of two optical paths.In addition,a band-pass filter with different cutoff wavelengths is established in front of the dual-path detectors to eliminate spectral overlap.A theoretical model is formulated by the ray tracing method to calculate the structural parameters of the optical system.The optimized design of the optical system is achieved by using ZEMAX and the optimal structural parameters are given.Test results show that the operating wavelength range is 800~2532 nm.Resolution is smaller than 12 nm(800~1600 nm)and17 nm(1600~2532 nm),and the overall size is 145 mm×135 mm×75 mm.This instrument has the advantages of wide spectrum,small volume,low cost and other advantages.