Coherent population oscillations with nitrogen-vacancy color centers in diamond

TL;DR

This paper investigates coherent population oscillations in nitrogen-vacancy centers in diamond using two-frequency microwave spectroscopy, revealing complex resonance structures and providing insights into relaxation mechanisms.

Contribution

It demonstrates the observation of coherent population oscillations in NV centers driven by two microwave fields and develops a theoretical model matching experimental results.

Findings

Observation of narrow Lorentzian resonances at the pump frequency.

Resonance widths depend on level lifetimes.

Agreement between experimental data and theoretical model.

Abstract

We present results of our research on two-field (two-frequency) microwave spectroscopy in nitrogen-vacancy (NV-) color centers in a diamond. Both fields are tuned to transitions between the spin sublevels of the NV- ensemble in the 3A2 ground state (one field has a fixed frequency while the second one is scanned). Particular attention is focused on the case where two microwaves fields drive the same transition between two NV- ground state sublevels (ms=0 -> ms=+1). In this case, the observed spectra exhibit a complex narrow structure composed of three Lorentzian resonances positioned at the pump-field frequency. The resonance widths and amplitudes depend on the lifetimes of the levels involved in the transition. We attribute the spectra to coherent population oscillations induced by the two nearly degenerate microwave fields, which we have also observed in real time. The observations agree well with a theoretical model and can be useful for investigation of the NV relaxation mechanisms.