Towards coherent optical control of a single hole spin: Rabi rotation of a trion conditional on the spin state of the hole

TL;DR

This paper demonstrates the optical control and detection of a single hole spin in a quantum dot, achieving Rabi rotations conditional on the spin state, advancing solid-state qubit manipulation techniques.

Contribution

It introduces a method for sequential preparation, control, and detection of a single hole spin with picosecond resolution in a quantum dot system.

Findings

Successful initialization of hole spin via electron tunneling

Observation of Rabi rotation conditional on hole spin

Potential for phase-shift operations in quantum computing

Abstract

A hole spin is a potential solid-state q-bit, that may be more robust against nuclear spin induced dephasing than an electron spin. Here we propose and demonstrate the sequential preparation, control and detection of a single hole spin trapped on a self-assembled InGaAs/GaAs quantum dot. The dot is embedded in a photodiode structure under an applied electric-field. Fast, triggered, initialization of a hole spin is achieved by creating a spin-polarized electron-hole pair with a picosecond laser pulse, and in an applied electric-field, waiting for the electron to tunnel leaving a spin-polarized hole. Detection of the hole spin with picosecond time resolution is achieved a second picosecond laser pulse to probe the positive trion transition, where a trion is created conditional on the hole spin to be detected as a change in photocurrent. Finally, using this setup we observe a Rabi rotation of the hole-trion transition that is conditional on the hole spin, which for a pulse-area of $2\pi$ can be used to impart a phase-shift of $\pi$ between the hole spin states, a non-general manipulation of the hole spin.