1.Research Center for Space Optical Engineering,Harbin Institute of Technology,Harbin;2.Beijing Institute of Tracking and Telecommunications Technology,Beijing;3.Shenzhen Research Institute, Harbin Institute of Technology
This paper establishes the modulation transfer function (MTF) and signal-to-noise ratio (SNR) characterization models under the diffraction efficiency influence, considering the diffraction optical imaging mechanism. Then, the imaging characteristics analysis model of the infrared array-aperture diffraction optical system is built based on the three-dimensional Finite Difference Time Domain (FDTD) method. Finally, the effects of different working wavelengths, field of views and filling factors on the imaging characteristics of the primary lens are analyzed. The analysis results show that the diffraction efficiency, the MTF and SNR of infrared array-aperture diffraction optical system all have spectral and spatial variation characteristics, and they reduce with the decrease of the filling factor. When the filling factor of the primary lens is 0.6, the integral area of MTF decreases by 45.42% and the SNR decreases by 4.92dB compared with the ideal full aperture system. The established model can be used to characterize the imaging quality of infrared array-aperture diffraction optical system and provide reference for the design of the imaging system.