数字微镜近红外光谱仪光学系统设计与实验

针对传统光谱仪体积大、成本高、检测速度慢、需样品前处理等不足,提出了利用数字微镜面阵（DMD）实现光谱谱面分割分时选通的近红外光谱仪光学系统.首先,对比传统光路介绍单探测器微型光谱仪系统测量原理|然后结合DMD特性提出光路方案,根据几何光学原理进行初步光学元件选型和光路结构设计,利用ZEMAX光学软件对光路进行仿真,确定结构参数|最后,搭建实验平台,进行光路测试.实验结果表明:该系统光路尺寸为70 mm×130 mm,测量波段为（900～1 500 nm）,分辨率可达19 nm|在能量损失较小的情况下,减小狭缝尺寸可提高光学分辨率,狭缝的极限尺寸为200 μm|减小狭缝子午面高度可减小谱面内弯曲现象.本系统基本满足近红外分光,实现单点探测器光谱测量的要求.

Design and Experiment of Digital Mcro-mirror Spectrometer Optical System

A compact,low cost,high speed,non-destructive testing NIR (near infrared) spectrometer optical system is developed based on digital micro-mirror device (DMD).The application of DMD as wavelength scanning element in a traditional lens optical system enables the design of compact grating spectrometers capable of acquiring full spectra using a single detector element.Firstly,comparing with the traditional optical system,there is a new structure with a single detector.With the characteristics of DMD,the structure of the spectrometer system is proposed.After calculating the parameters of the optical path,ZEMAX optical software is used to simulate the system.Finally,the prototype is fabricated and calibrated.Designed for a wavelength range between 900 nm~1 500 nm,the spectrometer optical system features a spectral resolution of 19nm with the area of 70 mm×130 mm.If the width of slit is more than 200 μm,decreasing its width can increase the resolution of this prototype and the change of intensity is slow.Adding an aperture in the prototype can reduce the curved of the slit image in the spectrum.The system satisfies the demand of Near Infrared(NIR) micro spectrometer with a single detector.