Circularly polarized light photodetector

The detection of circularly polarized light (CPL) is vital in a wide range of applications, such as drug screening, biosensing, imaging and quantum optics. However, traditional CPL detection methods use polarization devices to extract light chirality, which is difficult for system integration and miniaturization. This difficulty leads to the development of novel photodetectors that can directly respond to light chirality. Three main approaches are taken to achieve direct CPL detectors: material chirality, structural chirality and the nontrivial photodetection process, which can transfer spin information into the direction of the photocurrent. Here, we review the mechanisms and recent work of these three categories of direct CPL photodetectors.