Coupling of Epsilon-Near-Zero Mode to Mushroom-Type Metamaterial for Optimizing Infrared Suppression and Radiative Cooling

We report a complementary metal oxide semiconductor(CMOS)compatible metamaterial-based spectrally selective absorber/emitter(MBSSAE)for infrared(IR)stealth,which has the low absorption/emissivity in the IR atmospheric transmission window(3μm-5μm,8μm-14μm)and ultra-high and broadband absorption/emissivity in the IR non-atmospheric window(5μm-8μm).We propose a novel method for the broadband absorption/emissivity in 5μm-8μm with incorporation of an epsilon-near-zero(ENZ)material between the top patterned aluminum(Al)disks layer and the silicon oxide(SiO_(2))spacer layer.With an appropriate design,the peaks in the IR atmospheric transmission window can be suppressed while the peak intensity in the non-atmospheric window remains high.The optimized MBSSAE has an average absorption/emissivity less than 10%in 8μm-14μm and less than 6%in 3μm-5μm.And the average absorption/emissivity in 5μm-8μm is approximately over 64%.This proposed scheme may introduce the opportunities for the large-area and low-cost infrared stealth coating,as well as for the radiative cooling,spectral selective thermal detector,optical sensor,and thermophotovoltaic applications.