一种针对使用背照减薄型CCD器件色散型成像光谱仪的星上光谱定标方法

使用背照减薄型CCD器件的色散型成像光谱仪在近红外波段会出现呈条带状干涉条纹现象,该干涉条纹对入射光波长分布敏感,空间频率稳定,特别适用于微小光谱偏差的测量与校准.针对一台光栅色散型推扫式成像光谱仪样机,先估计出条纹分布的规律,再以此为基础,采用频域滤波、最小二乘拟合等方法提取干涉条纹中包含的相位信息,以此作为光谱定标的辅助参数.实验表明,当入射光强变化达到130％以上时,拟合谱线位置的不确定度最大为0.007 3 nm,模拟光谱位置改变后,以汞灯谱线作为基准光谱位置曲线,测得拟合算法的最大误差为0.135 8 nm,该结果证明,干涉条纹拟合定标方法可有效减少定标系统对光源稳定性的依赖,提高对光谱维微小偏移量的检测精度.

On-orbit spectral calibration for dispersive imaging spectrometer using back-illuminated CCDs

Dispersive imaging spectrometers that use back-illuminated CCDs have interference fringes in near-infrared band. These fringes are sensitive to the distribution of incident light wavelength and stable in spatial frequency. Therefore, they are very suitable for measuring and calibrating spectral deviation. In this paper, we built a grating dispersion push-broom imaging spectrometer prototype. We then estimated the distribution law of fringes and use band-pass filter and least squares method to extract the phase information of the interference fringes. Finally, we calculated the spectrum offsets based on this information. Experiments show that when the incident light intensity changes by more than 130%, the maximum uncertainty of fitting line positions is 0.0073nm. We change the spectral position and compare the spectral deviations calculated by using fitting algorithm and measured by using mercury spectrum. The maximum error of spectral position is 0.1358nm. Our fitting algorithm can effectively reduce dependence on light stability of the calibration system, and improve detection accuracy for slight offsets in spectral dimension.