Research On Active Control Material And Structure Of Infrared Thermal Radiation Based On VO₂

Mid-infrared atmospheric windows play an important role in infrared thermal imaging,infrared detection and radiative cooling.How infrared thermal emitters have the feature of adjustable radiation and selective radiation in mid-infrared atmospheric windows has become an important research hotspot in the field of electromagnetic metamaterials.At the same time,with the rapid development of phase-changing materials such as GST and VO₂,it is possible to actively control the electromagnetic properties of infrared emission structures.Based on the mechanism of magnetic resonance/standing wave mode multi-mode coupling,an infrared thermal emitter based on VO₂ is designed to show the radiation switching in a specific mid-infrared atmospheric window through active manner,and the special physical effects like infrared camouflage and infrared stealth are realized.The research contents and innovations of this paper mainly summarized as follows:?1?According to the characteristics of VO₂ films,the preparation process of VO₂films based on pulsed laser deposition and the preparation method of thick VO₂ films were optimized.The thermo-induced and Electro-induced phase transitions of VO₂ films are analyzed theoretically.The experimental results show that the electro-phase transition of VO₂ is induced by local Joule heat.?2?Based on the design of the infrared absorber,two kinds of thermal radiation active control emitters are designed:one is the emitter which has a absorption peak in the8-14?m band at high temperature and a absorption peak in the 5-8?m band at room temperature.At room temperature,the structure has a strong absorption peak at 5-8?m,which are coupled by three magnetic resonance absorption peaks.At high temperature,the absorption peak move to the 8-14?m band;the other one is the emitter which has a absorption peak in the 8-14?m band at room temperature and a absorption peak in the 5-8?m band at high temperature.At room temperature,the structure has a broadband absorption peak coupling with the 3^rd magnetic resonance mode and the 1^st standing wave mode.And its bandwith of 0.8 emissivity is 2.87?m.At high temperature,there is only1^st standing wave absorption peak at 5-8?m,while the emissivity at 8-14?m is less than0.2.Both of them realize the reversible switching of emission peaks inside and outside the mid-infrared atmospheric windows.This subject has hardly been studied in the infrared field.?3?Through thermal imaging experiments and theoretical analysis of infrared radiation,it is found that near the VO₂ phase transition temperature,the infrared thermal emitter has the effect of infrared camouflage.At the same time,it is found that the thermal emitter and the background material has identical radiation temperature at the specific temperature near room temperature,that is,the emitter's thermal image is concealed from background Al film at specific temperatures.