Recent Progress in Terahertz Quantum-Well Photodetectors

Terahertz quantum-well photodetectors (QWPs) represent a new and emerging photon-type detector in a terahertz region. Recent progress in the development of terahertz QWPs is reviewed. We first discuss the many-particle effects on the accurate design of terahertz QWPs. Second, three types of 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 multiquantum-well region of terahertz QWPs are enhanced. The performance of terahertz QWPs with these light couplers is improved significantly. Finally, terahertz-QWP-based wireless communication and imaging are demonstrated.