# Optically detected spin-mechanical resonance in silicon carbide membranes

## TL;DR

This paper introduces a theory of optically detected spin-mechanical resonance in silicon carbide membranes, enabling all-optical quantum sensing of magnetic fields and mass with high sensitivity without microwave fields.

## Contribution

It develops a novel theory of spin-mechanical resonance in SiC that allows optical detection of spin states and proposes new protocols for quantum sensing applications.

## Key findings

- Resonance causes a reduction in spin relaxation time via spin-phonon coupling.
- Photoluminescence intensity drops abruptly at resonance, enabling optical detection.
- Room-temperature nonlinear effects include spin-mediated cooling and heating.

## Abstract

Hybrid spin-mechanical systems are a promising platform for future quantum technologies. Usually they require application of additional microwave fields to project integer spin to a readable state. We develop a theory of optically detected spin-mechanical resonance associated with half-integer spin defects in silicon carbide (SiC) membranes. It occurs when a spin resonance frequency matches a resonance frequency of a mechanical mode, resulting in a shortening of the spin relaxation time through resonantly enhanced spin-phonon coupling. The effect can be detected as an abrupt reduction of the photoluminescence intensity under optical pumping without application of microwave fields. We propose all-optical protocols based on such spin-mechanical resonance to detect external magnetic fields and mass with ultra-high sensitivity. We also discuss room-temperature nonlinear effects under strong optical pumping, including spin-mediated cooling and heating of mechanical modes. Our approach suggests a new concept for quantum sensing using spin-optomechanics.