Interface reflection has been demonstrated to play an important role in GaAs multilayer homojunction far-infrared (FIR) detectors. A transfer matrix method that is able to provide a true optical field distribution within an FIR detector has been employed to optimize photon absorption and structure. The dependence of photon absorption on the reflectivity and the phase shift of the bottom mirror in a resonant-cavity-enhanced GaAs FIR detector has been investigated. Weak wavelength selectivity has been observed for both resonant and off-resonant FIR, which is a unique advantage for detector application. In comparison with the experimental result, a 20.8% increase in quantum efficiency was found in an optimized FIR detector.
© 2002 Optical Society of America
(230.5160) Optical devices : Photodetectors
(240.0310) Optics at surfaces : Thin films
(300.1030) Spectroscopy : Absorption
(300.6270) Spectroscopy : Spectroscopy, far infrared
(310.6860) Thin films : Thin films, optical properties
Haitao Luo, Yueheng Zhang, Wenzhong Shen, Yuan Ding, and Gang Yu, "Photon Absorption in Resonant-Cavity-Enhanced GaAs Far-Infrared Detectors," Appl. Opt. 41, 6537-6542 (2002)