基于MEMS技术的光栅结合可动Fabry-Perot腔微型光谱仪研究

Aiming at the problem of the decrease of the grating spectrometer resolution performance in the miniaturisation process, this project proposes a scheme of the combination of grating and tunable Fabry-Perot cavity based on MEMS technology and constructs a MEMS microspectrometer with wide FSR and high spectral resolution. The key reason for improving the spectral resolution will be analysed and the limitation of spectral resolution will be determined by the theoretical research on optical intensty modulation function and optical characteristics of combined dispersion model. The mechanics characteristics of micromirror plate in fabry-perot cavity will be studied to evaluate the influence on the parallelism of micromirror and control precision. The relationship between driving voltage and the displacement of electrode plate will be obtained. In addition, the dependence of the spectral measurement error and the work efficiency of microspectrometer on the modulation precision of cavity length of Fabry-Perot and the sampling rate of detector will be investigated in spectral scanning process. Meanwhile, the means of the synthesis of all spectrum and the calibration of wavelength will be also explored in the data processing. This project will be promote the application of MEMS technology in the spectral measurement field and the development of microspectrometer.

本项目针对光栅光谱仪微型化后分辨率会降低的问题，提出采用基于MEMS技术将光栅与可动Fabry-Perot腔组成联合色散模块的方案，构建一种宽自由光谱范围，高光谱分辨率的MEMS微型光谱仪。通过对联合色散模块光强调制函数以及光学特性的理论研究，分析提高光谱分辨率的主要因素，确定分光系统的极限光谱分辨率；对MEMS联合色散模块中的平动微镜极板进行力学分析，确立不同驱动结构下电压与极板位移的函数关系以及它们对MEMS平动微镜的平行度、控制精度等参数的影响。研究和分析在光谱扫描过程中可动Fabry-Perot腔腔长调制精度和探测器采样率对光谱测量误差以及工作效率的影响，并确定光谱扫描合成及波长定标等数据处理方式。研究成果有助于促进MEMS技术在光谱测量领域的应用，推动新型微型光谱仪的发展。

传统光栅光谱仪在微小型化后其光谱分辨率会降低，本项目提出了一种基于MEMS技术的光栅与可动Fabry-Perot腔联合色散模块，用以提高微型光谱仪的分辨率。针对该联合色散模块，建立了光强调制函数，理论分析了光学特性、结构匹配条件以及自由光谱范围、光谱分辨率等关键性能参数，确定了光谱分辨率增强性能。设计了一种基于体硅工艺的长腔联合色散模块MEMS芯片，仿真模拟了驱动电压与极板位移的动态力学特征，分析了光谱扫描过程中可动Fabry-Perot腔腔长调制步长对光谱测量误差的影响，确定了光谱扫描合成及数据处理方式。实验加工了基于静电驱动和基于陶瓷驱动的两种联合色散模块，构建了一种基于联合色散模块的微型光谱仪，该微型光谱仪相对于传统光栅光谱仪在自由光谱范围不变的条件下光谱分辨率可提高至少2倍。此外，还研究了一种基于棱镜阵列的“虚拟狭缝”，可有效增加微型光谱仪的光通量，提高系统信噪比。本研究为提高微型光谱仪性能提供了有效的技术手段，有助于促进MEMS技术在光谱测量领域的应用，推动新型微型光谱仪的发展。