All-optical noise spectroscopy of a solid-state spin

TL;DR

This paper introduces an all-optical noise spectroscopy method using coherent Raman rotations to analyze spin decoherence in solid-state qubits, overcoming limitations of microwave-based techniques.

Contribution

The authors develop a novel all-optical noise spectroscopy technique employing Raman rotations and Carr-Purcell-Meiboom-Gill sequences for solid-state spins.

Findings

Extracted noise spectra of nuclear spins in quantum dots.

Achieved spectral bandwidths over 100 MHz.

Enabled studies of spin decoherence without microwave fields.

Abstract

Noise spectroscopy elucidates the fundamental noise sources in spin systems, thereby serving as an essential tool toward developing spin qubits with long coherence times for quantum information processing, communication, and sensing. But existing techniques for noise spectroscopy that rely on microwave fields become infeasible when the microwave power is too weak to generate Rabi rotations of the spin. Here, we demonstrate an alternative all-optical approach to performing noise spectroscopy. Our approach utilizes coherent Raman rotations of the spin state with controlled timing and phase to implement Carr-Purcell-Meiboom-Gill pulse sequences. Analyzing the spin dynamics under these sequences enables us to extract the noise spectrum of a dense ensemble of nuclear spins interacting with a single spin in a quantum dot, which has thus far only been modeled theoretically. By providing spectral bandwidths of over 100 MHz, our approach enables the studies of spin dynamics and decoherence for a broad range of solid-state spin qubits.