Research on a precision temperature-controlled JT cooler for high operating temperature infrared detectors

Micro Joule-Thomson (JT) coolers are widely employed in infrared detectors due to their compactness and rapid cooling capability. However, traditional JT coolers lack active temperature regulation, limiting their suitability for emerging high-operating-temperature (HOT) infrared detector applications. To address this limitation, a prototype micro JT cooler driven by a micro-stepper motor was designed and fabricated to enable precise temperature control. A steady-state model of valve needle motion was developed and experimentally validated. Test results show that the precision temperature-controlled JT cooler delivers performance comparable to conventional designs in the liquid-phase working fluid region, while also enabling accurate temperature regulation in the gas-phase region. At target temperatures of 100 K, 110 K, 120 K, 130 K, and 140 K, the maximum temperature deviations were 2.9 K, 2.6 K, 3.5 K, 2.3 K, and 2.4 K, respectively — satisfying the requirements for HOT infrared detectors. This work successfully extends the technical advantages of micro JT coolers to HOT infrared detectors development.