Dual band nano structured anti reflection thin film coatings

Abstract

Dual band (3–5 μm and 8–12 μm) multilayer nano-structured antireflection thin films comprising alternate layers of ZrO₂ and SiO₂ were deposited on Silicon (100) substrate by RF magnetron sputtering. Peaks of both spectral windows were optimized during the design process to match the peak response of the sensor in the two spectra. The multilayer structure and morphology of the deposited films were analyzed by RBS, XRD, AFM and SEM. The transmission measurements showed an average transmission of T_avg ~ 93% in 3–5 μm and T_avg ~ 83% in 9–12 μm, making the structure effective in both spectral windows and useful in dual channel imaging applications.