To investigate water vapor, methane (CH₄), and carbon dioxide (CO₂) concentrations in the atmosphere, two near-infrared narrow band-pass filters are fabricated on sapphire substrates. The central wavelengths are 1375 nm and 1610 nm and bandwidths are 15 nm and 60 nm, with average transmission of 95%. Nb₂O₅/SiO₂ Fabry-Perot multilayer filters are optimized and deposited using dual ion beam sputtering. Compared to electron beam evaporated films, the dual ion beam sputtered films have significantly improved surface quality and reduced defects, and their root-mean-square surface roughness is reduced to below 1 nm, which significantly improves the uniformity of electric signals when coupled with a photodetector.