Low-noise membrane external-cavity surface-emitting laser for the optical excitation of NV-centres in diamonds

In this work, we present a low-noise, green laser specifically designed for the optical excitation of NV centres. The laser system consists of a single-mode 840 nm pump source coupled to a membrane external-cavity surfaceemitting laser (MECSEL) for wavelength selection at 1064 nm with an intracavity non-linear crystal for second harmonic generation. We describe the concept, development, and optimisation of the MECSEL system, from theoretical simulations to experimental implementation and laboratory characterisation, with a focus on achieving high efficiency, stability, and low-noise of the laser system components.