基于数字微镜器件的中阶梯光栅光谱仪设计方法及其谱图还原算法研究

The echelle spectrometer has the characteristics of hyper spectral resolution and full spectrum transient reading. It has gained very important applications in the field of atomic emission spectrometry which needs high-accuracy spectral measurement. At present, ICCD or EMCCD is mostly used as the detector of echelle spectrometer, which causes the high system cost. Meanwhile, the spectra reduction and wavelength accuracy need to be improved. These problems limit the further development of the echelle spectrometer. To solve the problems, the wavelength scanning echelle spectrometer based on DMD was designed. A DMD chip was introduced in the traditional optical path and specified wavelength was received by optimizing the spectra reduction algorithm and obtaining the corresponding relationship between wavelength and micro mirror. The theoretical corresponding relationship was ensured by high imaging quality optical design and the stray light suppression structure. According to the corresponding relationship, the wavelength received by the detector can be selected precisely. Receiving the wavelength by scanning the micromirror in a way and using PMT in replace of ICCD not only improve the wavelength accuracy, but also greatly reduce the system cost of the echelle spectrometer.

中阶梯光栅光谱仪集超高光谱分辨率和全谱瞬态直读的特性于一身，在需要进行高精度光谱测量的原子发射光谱领域得到非常重要的应用。目前，中阶梯光栅光谱仪多采用制冷型ICCD、EMCCD作为探测器，造成了高昂的系统成本，以及有待改善的谱图还原算法和波长准确度等问题，限制了中阶梯光栅光谱仪进一步发展。针对中阶梯光栅光谱仪存在的问题，本项目提出了基于数字微镜器件（DMD）的波长扫描式中阶梯光栅光谱仪，于传统光路中加入超高速DMD，通过谱图还原算法的优化升级，获取波长与DMD微镜单元的对应关系，实现指定波长的选择性高速接收。高成像质量的光学设计和杂散光抑制结构保证了还原算法所得对应关系的准确性，根据该对应关系可以精确筛选探测器接收到的波长。通过微镜单元高速扫描的方式依次获取波长，采用高灵敏光电倍增管（PMT）替换制冷型探测器，不仅提高了波长准确度，而且极大降低了中阶梯光栅光谱仪的系统造价。

中阶梯光栅光谱仪具有超高光谱分辨率和全谱瞬态直读的特点，在高精度光谱测量领域具有不可或缺的地位。针对中阶梯光栅光谱仪使用科学级探测器引起成本高昂，以及有待改善的谱图还原算法和波长准确度等问题，本项目开展基于数字微镜器件（DMD）的中阶梯光栅光谱仪设计方法及其谱图还原算法研究。目前，已完成基于DMD的波长扫描式中阶梯光栅光谱仪研制，于传统光路中加入超高速DMD，通过谱图还原算法的优化升级，获取波长与DMD微镜单元的对应关系，实现指定波长的选择性高速接收，仪器波段范围190~600nm，光谱分辨率达0.015nm@253.6521nm，能量集中度在单像素内达70%；构建包含像差修正功能的谱图还原算法，波长准确度提升至亚像元级别。DMD中阶梯光栅光谱仪有效降低系统成本同时实现“准瞬态直读”，其进一步研发对国产中阶梯光栅光谱仪产业化、扩展仪器应用领域具有非常重要的意义。