An Optical Spin Read-out Method for a Quantum Dot using the AC Stark Effect

TL;DR

This paper introduces a novel optical method for single-shot spin-state read-out in quantum dots using the AC Stark effect, achieving high fidelity detection with specific laser configurations.

Contribution

It presents a new technique employing the AC Stark effect and cycling transitions for efficient spin read-out in quantum dots, with detailed theoretical modeling.

Findings

Achieves 76.2% fidelity in spin read-out.

Demonstrates single-shot measurement capability.

Utilizes a Floquet-Liouville approach for modeling.

Abstract

We propose a method to read-out the spin-state of an electron in a quantum dot in a Voigt geometry magnetic field using cycling transitions induced by the AC Stark effect. We show that cycling transitions can be made possible by a red-detuned, circularly-polarized laser, which modifies the spin eigenstates and polarization selection rules via the AC Stark effect. A Floquet-Liouville supermatrix approach is used to calculate the time-evolution of the density matrix under the experimental conditions of a spin read-out operation. With an overall detection efficiency of 2.5%, the read-out is a single-shot measurement with a fidelity of 76.2%.