Towards stable, low-phase-noise, and multi-watt single frequency diamond lasers in the visible

Lasers of ultranarrow linewidth, stable single frequency, exceptional beam quality, and high power across versatile wavelengths in the visible spectrum are essential for a variety of applications including the generation of artificial guide stars, atom trapping in quantum experiments, and optical lattices for optical clocks. Diamond Raman lasers emerge as a promising solution since they can access wavelengths in the spectrum that no other laser can reach. They enable power scaling without compromising beam quality due to the exceptional diamond's thermal conductivity. Notably, Raman lasers offer a phase-noise-cleaning mechanism that is orders of magnitude superior to the traditional Brillouin lasers [1]. They inherently exhibit a spatial-hole-burning-free nature enabling the single-frequency laser operation [2]. However, achieving long-term stable single-frequency operation remains a significant challenge. To date, our group and others have demonstrated only short-term single-frequency operation, typically lasting from seconds to several minutes at power outputs in the few-watt range [3, 4]. This has been attributed to the higher order spatial stimulated Brillouin scattering (SBS) which causes chaotic high-frequency modes and also to the relatively broad Raman gain spectrum compared to the laser cavity's free spectral range which leads to multimode operation by the thermal effects at high power levels. In this contribution, we present our latest advancements in the development of high-power diamond Raman laser with exceptional spectral quality and stable single-mode operation in the visible.