Un-cooled cold background infrared scene emitters

In order to meet the requirement of the high altitude infrared scene, the new physical concept is proposed and hardware-in-the-loop facility is developed for simulating the cold background infrared scene. The infrared scene with cold background（－30℃）was achieved at the room temperature（300K）by putting the initially transparent semiconductor screen made of Ge in front of the cryogenic system and by controlling its local radiation coefficient which is less then forbidden gap. The effect of cold background generated by liquid nitrogen and semiconductor cooler, the variation of radiation power with read-in luminous power, and the temperature contrast of cold background and target are tested. The result shows that the cold background produced by liquid nitrogen is －30℃ while semiconductor is 3℃, the conversion efficiency of the semiconductor is increased with enhancement of read-in luminous power, but the excessive read-in luminous power leads to the saturation of radiation power, temperature contrast is obviously increased while the read-in luminous power is enhanced.