为了获得宽波段高分辨率的单色光, 对成像光谱仪进行了波长标定, 设计了一款扫描式三光栅单色仪。光栅扫描系统采用蜗轮蜗杆机构, 针对传统安装方式带来的光栅有效口径损失及杂散光等问题, 创造性地提出了蜗轮蜗杆转台偏轴安装的方法, 通过蜗轮蜗杆转台初始位置的偏移, 有效抑制了扫描过程中光栅实际有效口径的减小和仪器杂散光增加等问题。单色仪光学系统采用水平式C-T结构, 通过三块光栅实现280~2 240 nm的宽波段输出, 保证整个波段内的高衍射效率和光谱分辨率; 并针对蜗轮蜗杆的非线性扫描, 使用多种数学模型对单色仪系统进行了光谱定标。最终的实验和测量证明, 仪器在280~560 nm、560~1120 nm、1 120~2 240 nm三个波段的光谱分辨率分别为0.1、0.2、0.4 nm, 波长重复性分别为 0.094、0.186、0.372 nm, 波长准确度分别为0.096、 0.191、0.382 nm, 达到了设计目标, 满足成像光谱仪波长定标的使用要求。

In order to obtain wide-band and high-resolution monochromatic light, the wavelength of the imaging spectrometer was calibrated, and a scanning monochromator was designed. The grating scanning system was driven by worm and worm wheel mechanism, and an off-axis installation method was designed to install the worm gear, thus solving the problem of the traditional installation method, such as the decrease of the effective aperture of the grating, and the increase of the stray light. The monochromator optics system used the horizontal Czerny-Turner structure. It used three gratings to achieve 280-2 240 nm wide band output, which achieved the high diffraction efficiency and guaranteed the spectral resolution in the whole wavelength range. The output wavelength and the motor step number was non-linear in the process of worm gear scanning, so the monochromator system was calibrated by different mathematical models. The final experiment and the measurement proved that the spectral resolution of the monochromator was better than 0.1, 0.2, 0.4 nm at 280-560 nm, 560-1 120 nm, 1 120-2 240 nm respectively. Simultaneously the wavelength repeatability reached to 0.094, 0.186, 0.372 nm, and the precision reached to 0.096, 0.191, 0.382 nm. The monochromator achieves the design goals, and meets the requirements of the wavelength calibration of the imaging spectrometer.