Infrared scene projection optical system for blackbody micro cavity array

Abstract

The ground experiment of a spaceborne infrared detection system requires to generate infrared images that simulate infrared characteristics of space targets under laboratory conditions. The infrared images are physically generated by an infrared scene generator and projected to the detection system by an infrared scene projection optical system (IRSPOS). In this paper, a middle-wave IRSPOS (MW-IRSPOS) and a long-wave IRSPOS (LW-IRSPOS) are designed to operate in the cryogenic environment. The IRSPOSs have an operating temperature range of 100–350 K and operating wavebands of 3–5 μm and 8–10 μm, respectively. The thermal deformation of the IRSPOS structures is analyzed, and the IRSPOS structures are optimized to ensure the temperature adaptability. The LW-IRSPOS prototype is fabricated according to the analysis results, and the infrared scene projection experiment is carried out. Experimental results show that the modulation transfer function (MTF) of the LW-IRSPOS is higher than 0.21 at a spatial frequency of 13.5 lp/mm in the cryogenic environment. This LW-IRSPOS has been successfully applied to the ground experiment of a space infrared detection system.