Optimal Control Theory Techniques for Nitrogen Vacancy Ensembles in Single Crystal Diamond

TL;DR

This paper develops optimal control techniques for manipulating nitrogen vacancy ensembles in diamond, enabling improved quantum sensing capabilities without external magnetic fields.

Contribution

It introduces methods to control all four P.A.S. of NV ensembles in a single crystal diamond using OCT and circularly polarized microwaves, without static magnetic fields.

Findings

Successful control of all four P.A.S. in diamond NV ensembles

Implementation of OCT for collective spin control

Potential for high-sensitivity quantum sensors

Abstract

Nitrogen Vacancy Center Ensembles are excellent candidates for quantum sensors due to their vector magnetometry capabilities, deployability at room temperature and simple optical initialization and readout. This work describes the engineering and characterization methods required to control all four Principle Axis Systems (P.A.S.) of NV ensembles in a single crystal diamond without an applied static magnetic field. Circularly polarized microwaves enable arbitrary simultaneous control with spin-locking experiments and collective control using Optimal Control Theory (OCT) in a (100) diamond. These techniques may be further improved and integrated to realize high sensitivity NV-based quantum sensing devices using all four P.A.S. systems.