Readily fibre-coupled static microcavity for exploring NV^– lasing

<p dir="ltr">The realization of a continuous wave laser from the nitrogen-vacancy (NV^–) color centres in diamond is proposed as an efficient scheme to improve the sensitivity of room-temperature magnetometers. This thesis develops a stable as well as static microcavity to explore NV^– centres as the gain medium for achieving lasing. The cavity is readily fibre-coupled, making its transmission easily accessible for detection. The cavity is in the Fabry-Pèrot configuration, with the reflective surfaces formed by a flat macroscopic mirror substrate, and a DBR coated optical fibre tip. The cavity loaded with diamond containing NV^– spins is placed in vacuum to enhance stability. The cavity was characterized for near infrared wavelength emission of NV^– spins and a quality factor of 9575 was estimated at 790 nm. The preliminary measurements utilising the same center wavelength were used to calculate a cavity finesse of 10.7 for an effective cavity length of 349.2 micrometers. Furthermore, the emission of NV^– spins into the cavity modes was explored and a preliminary measurement for its power dependence was performed. Finally, the observed power dependence was analysed with respect to the laser threshold conditions, shedding light on the feasibility of achieving lasing through the parameters considered in this thesis. The experimental study presented in this thesis has implications for the development of miniaturized NV^– laser for room-temperature magnetometry.</p>