Type-Ii Inas/Gasb Superlattices For Dual Color Infrared Detection

Midwave-midwave dual color detection has been successfully demonstrated by using pixel filters fabricated on top of InAs/GaSb focal plane arrays (FPAs). The pixel filters used in these FPAs were designed to transmit infrared radiation in the 3.5 - 4.1 mu m wavelength region and to completely block light shorter than 3.5 mu m. By comparing the signals of filtered and unfiltered pixels, excellent contrast between the two bands were obtained. This design concept offers a great flexibility to tailor the transmission window to any wavelength range within the 3-5 mu m wavelength region. In particular, this dual color detector concept has been used for gas detection of volatile organic compounds which have main absorption peaks at 3.3 mu m.