Infrared Absorption And Thermal Emission Performance Of Nanostructures

Micro-nano photonics is the field to study the interaction between light and matter at micro-nanoscale and its rules.Micro-nano devices have attracted extensive attention in recent years for their modulation in light generation,transmission and detection.The infrared light is widely used in infrared stealth,energy applications and industrial monitoring because of its remarkable thermal effect.By combining the modulation effect of micro-nano structures and the thermal effect of infrared light,the modulation of infrared absorption/emission can be realized.Traditional micro-nano-infrared structures statically modulates the wavelength,intensity,direction,and bandwidth of infrared performances by changing the shape,materials,and geometric sizes of gratings,photonic crystals,FP cavities and metamaterials.By applying active materials such as semiconductor quantum wells,graphene,and vanadium oxide to the micro-nanostructures,the infrared performance of the devices can be dynamically modulated.However,sustaining extra sources such as high temperatures and bias voltages should be applied to realize the dynamic modulation,which increases the complexity and energy consuming.Despite the fact that micro-nano-infrared devices have achieved a variety of modulations of infrared performance,few practical applications have been realized.Based on these conditions,this paper is focused on tunable micro-nano infrared devices and the applications of micro-nano infrared devices.We introduce several zero-static-power tunable micro-nano absorbers/emitters.The applications of micro-nano infrared devices in the field of infrared detection and thermal modulation are also investigated.We apply the phase changing material Ge2Sb2Tes(GST)to micro-nano devices in order to achieve tunable infrared absorbers/emitters.We designed an absorber/emitter with tunable absorptivity/emissivity from 0.2 to 1 based on the significant change of the infrared property of GST caused by the phase transition.Then we introduced two kinds of wavelength-tunable absorbers/emitters.The light penetration in metal and the enhanced electric field in the thin metal film lead to high absorptivity/emissivity during the tunable wavelength.The absorptivity/emissivity keeps above 0.6 when the peak wavelength is tuned from 7 ?m to 13 ?m.Finally,a bandwidth-tunable absorber/emitter is introduced based on the GST photonics crystal.By controlling the phase transition of GST,the bandwidth of the absorber/emitter can be switched between 200 nm and 4.5 ?m.Dual-peak absorption/emission can also be realized if the contribution of the plasmonic resonance and FP resonance is balanced.The above three kinds of absorbers/emitters have the advantage of stability owing to stability of GST.Zero static power is needed to maintain the infrared performance of the devices.In infrared applications of micro-nano devices,we first studied microbolometers based on the metamaterial absorbers.We calculated the absorption of the metamaterial absorbers in the mid-infrared region and the photothermal effect of microbolometers.A wavelength-selective microbolometer is realized.Then we designed some transparent thermal insulation material based on silver nanofibers and ultra-thin metal films,respectively.By optimizing the diameter and spacing of the silver nanofibers,both the visible light transmissivity and the infrared reflectivity exceed 0.8.Then we studied the performance of the ultra-thin metal film on the surface of SiO2 and PE.By controlling the Au thickness,the average visible transmissivity exceeds 0.6 and the mid-infrared reflectivity reaches 0.9 and 0.8 respectively.Based on the current research progress,we further look into the research directions of tunable micro-nano infrared devices and the application prospects of micro-nano infrared devices.