Microwave mode cooling and cavity quantum electrodynamics effects at room temperature with optically cooled nitrogen-vacancy center spins

Recent experimental and theoretical studies demonstrated microwave mode cooling and cavity quantum electrodynamics (C-QED) effects at room temperature by using optically cooled nitrogen-vacancy (NV) spins. This article explores improvements by analyzing parameters from recent diamond maser experiments with a high-frequency microwave resonator. A more complete treatment of optical pumping and dissipation in NV centers is provided, studying the dependence on laser power. The study predicts microwave photon number reduction to 261 (116 K), five times lower than previously reported. Laser-power-controlled C-QED effects across weak-to-strong coupling regimes are predicted, observing saturation under strong laser pumping. The model can be adapted for other solid-state spins and C-QED effects in maser operation.

Yuan Zhang, Qilong Wu, Hao Wu, Xun Yang, Shi-Lei Su, Chongxin Shan, Klaus Mølmer