Resonant Cavity-Enhanced Multicolor Polarization Sensitive Quantum Dot Infrared Photodetector

We propose a resonant cavity-enhanced polarization sensitive photodetector based on intersubband transitions of holes in valence band of InGaAs/GaAs elongated quantum dots (QDs). The elongation of the QDs has been considered along in-plane dimension to get the polarization resolved photocurrent for normal incidence of light. The detector is capable of detecting photons of wavelength ranging from 11 to 13 μm. Absorption coefficient, quantum efficiency, optical gain, and photocurrents have been calculated. It is found that the maximum current in conventional photodetector is inadequate to distinguish photocurrents for different angles of polarization of incident light. The performance of the proposed device is significantly enhanced by the incorporation of resonant cavity structure. It is found that resonant cavity structure is useful in increasing the ratio of orthogonal polarization states of incident light. The role of mirror reflectivity and the length of cavity are also discussed, which are found to be crucial for the device performance.