Design of terahertz quantum-well photodetectors

Terahertz quantum-well photodetectors (QWPs) represent a new and emerging photon-type detector in terahertz region. We first discuss the many-particle effects on the accurate design of terahertz QWPs. Grating and metal-cavity light couplers for terahertz QWPs are introduced. At resonant coupling frequencies, the polarization of light field is effectively changed by the light couplers to fulfill the selection rule of intersubband transition. Meanwhile, the electric field intensities in the active multi-quantum-well region of terahertz QWPs are enhanced. The performance of terahertz QWPs with these light couplers is improved significantly.