Magnetic-Field-Dependent Stimulated Emission from Nitrogen-Vacancy Centres in Diamond

TL;DR

This paper experimentally demonstrates magnetic-field-dependent stimulated emission from NV-centres in diamond, achieving record contrast and power, advancing quantum sensing and laser applications.

Contribution

It provides the first experimental demonstration of laser threshold magnetometry with NV-centres, showing magnetic-field-dependent stimulated emission with high contrast.

Findings

Stimulated emission amplified by 64% in NV-centres

Record 33% magnetic contrast in emission

Maximum output power in the milliwatt range

Abstract

Negatively charged nitrogen-vacancy centres in diamond are promising quantum magnetic field sensors. Laser threshold magnetometry has been a theoretical approach for the improvement of NV-centre ensemble sensitivity via increased signal strength and magnetic field contrast. In this work we experimentally demonstrate laser threshold magnetometry. We use a macroscopic high-finesse laser cavity containing a highly NV-doped and low absorbing diamond gain medium that is pumped at 532nm and resonantly seeded at 710nm. This enables amplification of the signal power by stimulated emission of 64%. We show the magnetic-field dependency of the amplification and thus, demonstrate magnetic-field dependent stimulated emission from an NV-centre ensemble. This emission shows a record contrast of 33% and a maximum output power in the mW regime. These advantages of coherent read-out of NV-centres pave the way for novel cavity and laser applications of quantum defects as well as diamond NV magnetic field sensors with significantly improved sensitivity for the health, research and mining sectors.