Coupling spin defects in hexagonal boron nitride to a microwave cavity

TL;DR

This paper demonstrates a microwave cavity design that enhances the coupling and sensitivity of spin defects in hexagonal boron nitride for quantum sensing applications.

Contribution

The authors design and fabricate a microwave double arc resonator that improves microwave delivery and coupling to spin defects in hBN, enhancing quantum sensing capabilities.

Findings

Achieved a magnetic field sensitivity of 42.4 μT/√Hz.

Enhanced ODMR contrast through cavity coupling.

Reduced linewidth of ODMR signals.

Abstract

Optically addressable spin defects in hexagonal boron nitride (hBN) have become a promising platform for quantum sensing. While sensitivity of these defects are limited by their interactions with the spin environment in hBN, inefficient microwave delivery can further reduce their sensitivity. Hare, we design and fabricate a microwave double arc resonator for efficient transferring of the microwave field at 3.8 GHz. The spin transitions in the ground state of VB- are coupled to the frequency of the microwave cavity which results in enhanced optically detected magnetic resonance (ODMR) contrast. In addition, the linewidth of the ODMR signal further reduces, achieving a magnetic field sensitivity as low as 42.4 microtesla per square root of hertz. Our robust and scalable device engineering is promising for future employment of spin defects in hBN for quantum sensing.