# Purcell-Enhanced Single-Photon Generation from CsPbBr3 Quantum Dots in In Situ Selected Laguerre–Gaussian Modes

## TL;DR

This paper demonstrates a method to directly generate single photons in specific light patterns using quantum dots and microcavities, which could improve quantum communication and imaging.

## Contribution

The study introduces a direct method for generating single photons in Laguerre–Gaussian modes using CsPbBr3 quantum dots and a microcavity.

## Key findings

- Single photons were generated with up to 18.1 times faster decay rates using a microcavity.
- In situ tuning allowed selective coupling to different LG modes and observation of their spatial patterns.
- The method enables high-rate generation of single photons with orbital angular momentum.

## Abstract

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.