# Cavity-enhanced optical readout of a single solid-state spin

## TL;DR

This paper demonstrates a cavity quantum electrodynamics technique for optical readout of a single solid-state electron spin in a quantum dot, achieving a fidelity of 0.61 with potential for improved efficiency.

## Contribution

It introduces a cavity-enhanced optical method for single-spin readout in quantum dots, enabling projective measurements with high fidelity.

## Key findings

- Achieved spin readout fidelity of 0.61.
- Demonstrated cavity reflectivity depends on spin state.
- Showed potential for fidelity improvement with better photon collection.

## Abstract

We demonstrate optical readout of a single electron spin using cavity quantum electrodynamics. The spin is trapped in a single quantum dot that is strongly coupled to a nanophotonic cavity. Selectively coupling one of the optical transitions of the quantum dot to the cavity mode results in a spin-dependent cavity reflectivity that enables projective spin measurements by monitoring the reflected intensity of an incident optical field. Using this approach, we demonstrate spin readout fidelity of 0.61 for a quantum dot that has a poor branching ratio of 0.43. Achieving this fidelity using resonance fluorescence from a bare dot would require 43 times improvement in photon collection efficiency.

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Source: https://tomesphere.com/paper/1706.05582