Laser Direct Writing of Visible Spin Defects in Hexagonal Boron Nitride for Applications in Spin-Based Technologies

TL;DR

This paper demonstrates a laser-based method to precisely create and control spin defects in hexagonal boron nitride, advancing the development of on-chip quantum sensors and spin-based quantum devices.

Contribution

It introduces a deterministic femtosecond laser writing technique for generating spin defects in hBN, expanding beyond the previously limited defect types.

Findings

Successful creation of spin defect ensembles with spectra from 550 nm to 800 nm.

Detection of positive ODMR signals with up to 0.8% contrast.

Efficient and deterministic fabrication of bright spin defect arrays.

Abstract

Optically addressable spins in two-dimensional hexagonal boron nitride (hBN) attract widespread attention for their potential advantage in on-chip quantum devices, such as quantum sensors and quantum network. A variety of spin defects have been found in hBN, but no convenient and deterministic generation methods have been reported for other defects except negatively charged boron vacancy ($V_B^-$). Here we report that by using femtosecond laser direct writing technology, we can deterministically create spin defect ensembles with spectra range from 550 nm to 800 nm on nanoscale hBN flakes. Positive single-peak optically detected magnetic resonance (ODMR) signals are detected in the presence of magnetic field perpendicular to the substrate, and the contrast can reach 0.8%. With the appropriate thickness of hBN flakes, substrate and femtosecond laser pulse energy, we can deterministically and efficiently generate bright spin defect array. Our results provide a convenient deterministic method to create spin defects in hBN, which will motivate more endeavors for future researches and applications of spin-based technologies such as quantum magnetometer array.