Investigating Color Centers in Diamond for Microwave Quantum Technologies

The rapid advancement of quantum technology in recent years has necessitated the development of many specialized microwave components such as the Josephson parametric amplifier (JPA), to be used in conjunction with superconducting qubits. In this thesis, present research into impurity spins in diamond, which include nitrogen (P1), nitrogen vacancy (NV), and vacancy clusters, in particular (R5) centers, for use in these microwave quantum technologies. I first present the development of a 3D loop-gap microwave resonator for use with these impurity spins. We were able to demonstrate strong coupling with an ensemble of nitrogen-vacancy (NV) centers as well as that of nitrogen (P1) centers at 10 mK. I next demonstrate two separate but related maser effects in the spin ensemble. The first of which is a thermally-generated inversion of the NV centers, produced by an abrupt cooling of the sample with a lifetime of several hours. Finally, I demonstrate another spin-based cavity maser, this time using the P1 centers and an active microwave pumping scheme. This cavity amplifier has several desirable qualities, including a large gain and low noise temperature. Such an amplifier may be promising for future quantum technology applications.Okinawa Institute of Science and Technology Graduate Universit