Nonlinear optical pumping to a diamond NV center dark state

TL;DR

This study reveals that a dark state in diamond NV centers is accessed via two-photon pumping into a specific quartet state, affecting their photodynamics and enabling local infrared field sensing, which impacts quantum technology applications.

Contribution

It demonstrates nonlinear optical pumping into a specific NV center state, constrains its energy levels, and introduces a method for sensing local infrared fields.

Findings

Dark state accessed by two-photon pumping into $^4A_2$ state.

Constraints on energy levels of the dark state and recombination threshold.

Enables sensing of local infrared fields using NV centers.

Abstract

The photodynamics of diamond nitrogen-vacancy (NV) centers limits their performance in many quantum technologies. Quenching of photoluminescence, which degrades NV readout, is commonly ascribed to a dark state that is not fully understood. Using a nanoscale cavity to generate intense infrared fields that quench NV emission nonlinearly with field intensity, we show that the dark state is accessed by two-photon pumping into the $^4A_2$ quartet state of the neutrally charged NV (NV$^0$). We constrain this state's energy relative to the NV$^0$ ground-state ($^2E$) to $>0.58$\,eV and the recombination energy threshold to the NV$^-$ ground state ($^3A_2$) to $<2.01$ eV. Furthermore, we show that accessing this state allows sensing of local infrared fields. This new understanding will allow predictions of the limits of NV technologies reliant upon intense fields, including levitated systems, spin--optomechanical devices, and absorption--based magnetometers.