Ultrasensitive MoTe ₂ Circular Polarization Detectors with Monolithically Integrated Liquid Crystal Bifocal Lens

Recent advances in polarization-sensitive photodetection have highlighted the growing importance of circular polarization discrimination in emerging optoelectronic applications. We report a novel integrated photodetector system that combines a liquid crystal bifocal lens with two-dimensional MoTe2 to achieve the high-sensitivity detection of circularly polarized light (CPL) without conventional optical components. The device delivers an exceptional anisotropy factor (gIph) of up to 0.49 for circular polarization discrimination─ranking among the highest values reported to date for integrated CPL detectors. The spatially resolved left- and right-handed circularly polarized beams are independently detected by optimized MoTe2 photodetector channels, which exhibit outstanding optoelectronic performance, including a high responsivity of 120 A/W and a specific detectivity of 4.35 × 1011 Jones at 1064 nm illumination. The monolithic integration approach significantly reduces system complexity compared with traditional polarization detection setups, enabling a compact, high-performance solution for circular polarization detection with promising applications in quantum optics, optical encryption, and biosensing.