基于数字微镜器件的中阶梯光栅光谱仪的光学系统设计

研究了一种基于数字微镜器件(DMD)具有新型光路结构的中阶梯光栅光谱仪,并采用新的谱图信息接收方式来降低其使用成本和数据处理过程的复杂程度。将具有单波长选通功能的DMD与一维探测器光电倍增管(PMT)相结合接收中阶梯光栅光谱仪的光谱信息,在降低仪器成本的同时将中阶梯光栅光谱仪谱图还原算法与DMD扫描驱动算法相整合,提高了算法效率。由于DMD的填充因子比CCD稍低,该类光谱仪对成像质量和能量集中度提出了更高的要求。本文根据DMD型中阶梯光栅光谱仪特点,在有限的可挑选的光学材料下,采用多重优化的方式合理设计了中阶梯光栅光谱仪准直镜、中阶梯光栅、棱镜、聚焦镜等各个光学元件的光路结构参数,并且在Czerny-Turner结构中加入校正透镜和场镜,校正了系统所有像差,提高了整个光学系统的成像质量和光谱分辨率。最终设计的光谱仪系统分辨率达0.01nm,单个微反射镜内的光斑能量聚集度达到70%。

Optical system of echelle spectrometer based on DMD

An echelle spectrometer with a new optical path based on a Digital Micro Device (DMD)was proposed and a new spectrum receiving method was used to reduce the cost of the grating spectrograph and the complexity of data processing. The DMD with single wavelength getting function and an one-dimensional photomultiplier (PMT) were combined to receive spectral information of the echelle spectrometer. By which, the cost of the instrument was reduced and the spectral restore algorithm for the echelle spectrometer and the scan driving algorithm for the DMD were integrated to improve algorithm efficiency. Because the fill factor of CCD is lower than that of DMD, this kind of echelle spectrometer should be giving a higher imaging quality and higher imaging energy. According to the characteristics of the echelle spectrometer and the limited range of selected optical materials, the multi-optimization method was employed to design the optical path structure parameters of the echelle spectrometers such as quasi-direct mirror, echelle grating, prism and focusing mirror. Moreover, the Czerny-TurnerC-T structure was added into the system to correct the asymmetric aberration and three correction lenses was used to correct the spherical aberration astigmatism. Finally, the resolution of the designed spectrometer system has reached 0.01 nm and the system imaging energy in one pixel can be 70%.