Ultrathin, High-Performance Circular Wave Plate Based on Natural van der Waals Crystals

Circularly polarized light (CPL) holds immense promise for diverse applications, including three-dimensional(3D) displays, quantum information processing, biosensing, and optical imaging. However, high-performance, ultrathin, and easily integrable devices for CPL manipulation and discrimination remain a significant challenge. Leveraging the phase modulation capability of the natural two-dimensional (2D) van der Waals material NbOCl ₂ and the polarization selectivity of MoOCl ₂ , we propose and demonstrate a lithography-free, facilely fabricated, and ultrathin circular polarization wave plate. Experimental characterization demonstrates that the fabricated MoOCl ₂ /NbOCl ₂ stacked nanoplates, with a thickness of merely ~690 nm, exhibit significant selectivity for left- and right-handed CPL across the visible spectrum, achieving a maximum extinction ratio of 14.72 dB. Furthermore, by integrating the stacked device into a light-emitting diode (LED) chip, we achieve high-quality circularly polarized emission is obtained at specifically designed wavelengths, with a degree of circular polarization (DOCP) reaching 98.72%. This work provides a versatile strategy for constructing ultrathin, integrable circularly polarized photonic devices by leveraging the intrinsic optical anisotropy of natural low-dimensional materials, and demonstrates broad application prospects in chiral light-field detectors and on-chip circularly polarized light sources.