针对实验方法获取光谱响应函数存在时效性差和过程复杂的特点,提出了一种基于惠更斯点扩散函数仿真光谱响应函数及光谱分辨率的方法,该方法综合考虑衍射及像差信息,在光学设计阶段即可获得任意标称波长处的精细光谱响应函数及光谱分辨率.对自行设计的工作范围为1 000 nm~2 500 nm的光栅光谱仪进行单波长及全谱段光谱响应函数仿真,并以几何光线追迹法作为对比.结果表明,基于惠更斯点扩散函数仿真的光谱响应函数带宽始终大于后者获得的带宽,在全波段范围内二者偏差介于2%~5%,且前者变化会同时受衍射及像差影响.两种方法对数坐标表示的光谱响应函数比较表明,相对强度在10－2~10－5时,衍射效应明显,而低于10－5时仿真结果中衍射的影响可以忽略.该方法对分辨率为10 nm的光谱仪仿真过程中产生不确定度为0.25nm.

As acquiring spectral response function by experimental method is always time limited and with a complicate process,a simulation of spectral response function and spectral resolution based on huygens point spread function was suggested. Taking into account the effects of optical aberration and diffraction,the fine spectral response function curves and spectral resolution at any nominal wavelength of the full spectral range can be calculated as early as in the design phase. A grating spectrograph with a spectral range from 1 000 nm to 2 500 nm was proposed for illustrating the simulation process. With a geometrical ray tracing method as a comparison,the spectrograph′s spectral response function at single wavelength and full spectral range are simulated by huygens point spread function method. The results demonstrate that the full width at half maximum of spectral response function acquired by huygens point spread function method is greater than the result of geometrical ray tracing method at any wavelength. The relative deviation changes from 2% to 5% for the full spectral range. Both optical aberration and diffraction affect the result of huygens point spread function method. At last,the comparison of spectral response function curves acquired by the two methods is shown with logarithmic scale for the y-axis. The results show that the effect of diffraction is dominant when relative response between 10－2 and 10－5 and can be neglected below 10－5. The uncertainty of the simulated process for the spectrograph with a 10nm spectral resolution is 0.025 nm.