Purcell-Enhanced Single-Photon Generation from CsPbBr ₃ Quantum Dots in In Situ Selected Laguerre–Gaussian Modes

Single photons in Laguerre-Gaussian (LG) beams, which carry orbital angular momentum (OAM), could enable more robust and efficient photonic quantum communication and information processing, as well as enhanced sensitivity in quantum metrology and imaging. However, as most implementations are indirect or require additional mode-shaping elements, the direct generation of single photons with OAM has received growing interest. Colloidal lead halide perovskite quantum dots (QDs) have recently emerged as a versatile material that can produce indistinguishable single photons quasi-deterministically at a high rate. Here, we integrate single CsPbBr₃ QDs into an open Fabry-Perot microcavity with a nanofabricated Gaussian-shaped deformation, demonstrating Purcell-enhanced single-photon generation into individual cavity modes with up to 18.1 ± 0.2 times accelerated decay, down to tens of picoseconds. By in situ tuning of the cavity resonance, we can selectively couple a single QD to different LG modes and observe the spatial patterns of the generated single-photon beams emitted from the cavity. Our findings may guide the development of high-photon-rate sources that directly generate single-photon LG beams for advanced quantum photonic applications.