Thermo-optic tunable thin-film filter based on Fabry-Perot(F-P) cavity structure is a very attractive alternative integrated optical device.In this simulation-based paper,the key performance of typical thermo-optic tunable F-P filter is discussed by analyzing the structure of Distributed Bragger Reflectors(DBR) and the thermo-optic property of cavity thin-film material.The results indicate a negative correlation between the number of DBR periodical layers and full width at half maximum(FWHM),and a proportional relation between thermal-optic coefficient of material and tuning range.In addition,the cavity is more sensitive to the optical property than the reflection layers according to the analysis of thickness error of the film.And to solve slow thermal response without incurring other performance loss,a novel structure of the suspended cavity is proposed,in which only the cavity is heated.
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.
