A Circular Photogalvanic Effect-Controlled Polarimeter based on a Bipolar Phototransistor Utilized in Spatially Resolved Mapping

The circular photogalvanic effect (CPGE), converted from the photon angular moment as a spin-polarized charge current via inversion asymmetry, is an effective approach to detecting circularly polarized light. However, the CPGE current is typically weak, and even the electrical gate gives quite limited improvement, necessitating the use of auxiliary amplifiers to strengthen the signals for practical applications. Here, we constitute a vertical bipolar phototransistor based on MoS2/ZrGeTe4/MoS2 heterojunction with a noncentrosymmetric active region, which can detect and amplify the CPGE photocurrents for all directions, with a CPGE gain of 25. Thereupon, we achieve tens of μA/W CPGE responsivity from visible to near-infrared (NIR) and wide acceptance angles from 45° to -45° at room temperature, revealing multiscenario applications. The full Stokes spatially resolved mapping of the NIR vortex beam demonstrates its practical applicability as a polarimeter with high sensitivity. Our work provides an approach to developing nanostructured polarimeters controlled by inversion symmetry and devoid of external amplification modules, which leads to potential applications for future nanophotonics and optoelectronic nanodevices.