Coherent Control of Nitrogen Vacancy Centers in Diamond using Broadband Micro-coil Antennas

Quantum sensing technology has revolutionized how we measure and detect material properties. For example, ensembles of negatively charged nitrogen-vacancy centers in diamonds are highly sensitive to local magnetic fields, allowing magnetometry in the femtotesla range, as well as to adjacent nuclear spins for optically-detected magnetic resonance spectroscopy at nanometer scales. We have built a quantum sensing platform which demonstrates these capabilities.

We report our recent progress in the design, simulation, and characterization of several planar microcoil antennas for coherent spin control in a broadband frequency range. We evaluate the benefits of these designs, and introduce and validate a new antenna configuration which has shown excellent spatial uniformity over an area of 0.05 mm2. We show these antennas enable high-contrast electron paramagnetic resonance detection and extended coherent time in Rabi oscillations, which are essential for the success of quantum sensing applications. We demonstrate that these antennas are compatible with transparent and thin substrates, and we explore the use of magnetic flux concentrators to improve magnetic field sensing precision, enabling a flexible and compact platform for a range of sensing applications.