Twist-stacked black phosphorus for wide-spectral chiral photodetection

On-chip integrable circularly polarized light (CPL) detectors hold significant potential for applications in optical communications, bioimaging, quantum information, and intelligent sensing, enabling chip-scale chiral light detection and information processing. However, current developments in materials and structural designs struggle to achieve wide-spectral detection capability while maintaining high circular polarization discrimination. This limitation significantly constrains the practical applicability of such detectors in complex environments and object detection scenarios. Herein, we propose a CPL detector based on a twist-stacked black phosphorus (b-p) system. By utilizing twisted b-p as an artificially constructed unit with chiral response and designing a symmetry-stacked sandwich structure in space, we achieve bipolar circular polarization detection and imaging across a wide wavelength range (from visible light to mid-infrared), with peak responsivity reaching 0.1 A/W. This design demonstrates both theoretically and experimentally the feasibility of utilizing a twist-stacked b-p system for wide-spectral CPL detection. This advancement offers valuable insights for addressing the bottlenecks in chip-integrated CPL detection technology. On-chip circularly polarized light (CPL) detectors are relevant for various applications, but current approaches have shown a trade-off between wide spectral detection range, high discrimination ratio and high polarization sensitivity. Here, the authors report broadband high-performance CPL detectors based on twisted black phosphorus structures.