Towards practical circularly polarized luminescence: Carbon dots-based circularly polarized lasers

Circularly polarized luminescence (CPL) has significant application value in fields such as quantum computing, three-dimensional (3D) display, and bioimaging. However, its practical application faces challenges including low dissymmetry factor (g), insufficient quantum yield, poor directionality, and broad emission spectrum. To address these issues, circularly polarized laser technology can significantly enhance CPL performance through stimulated emission amplification and resonant cavity mode selection, achieving circularly polarized light output with high g (close to the theoretical limit of 2), high brightness, narrow linewidth, and strong directionality. Currently, although materials like organic microcrystals and perovskites can realize circularly polarized laser with high g, they still have problems such as complex preparation and poor biocompatibility. In contrast, carbon dots (CDs) have emerged as a highly promising new type of circularly polarized gain medium due to their advantages of simple preparation, low cost, low toxicity, easy modification, and good biocompatibility. This paper systematically reviews the material systems, device types, and application progress of circularly polarized laser, focusing on the advantages of CDs as gain media and their potential in fields such as 3D display, optical communication, information encryption, and biosensing. It also prospects the future development directions and challenges of CDs-based circularly polarized lasers, providing a reference for promoting the practical application process of high-performance circularly polarized laser devices.