Diamond Raman laser: a promising high-beam-quality and low-thermal-effect laser

Abstract

Stimulated Raman-scattering-based lasers provide an effective way to achieve wavelength conversion. However, thermally induced beam degradation is a notorious obstacle to power scaling and it also limits the applicable range where high output beam quality is needed. Considerable research efforts have been devoted to developing Raman materials, with diamond being a promising candidate to acquire wavelength-versatile, high-power, and high-quality output beam owing to its excellent thermal properties, high Raman gain coefficient, and wide transmission range. The diamond Raman resonator is usually designed as an external-cavity pumped structure, which can easily eliminate the negative thermal effects of intracavity laser crystals. Diamond Raman converters also provide an approach to improve the beam quality owing to the Raman cleanup effect. This review outlines the research status of diamond Raman lasers, including beam quality optimization, Raman conversion, thermal effects, and prospects for future development directions.

A comprehensive review on the development and applications of narrow‐linewidth lasers

“…In addition, the Brillouin laser and Brillouin frequency comb based on the Raman conversion were demonstrated in the same group 93,94 . Owing to the excellent optical and thermophysical properties of diamond, diamond Brillouin lasers exhibit high power and wavelength scalability 95–97 …”

“…93,94 Owing to the excellent optical and thermophysical properties of diamond, diamond Brillouin lasers exhibit high power and wavelength scalability. [95][96][97]…”

A review of ns-pulsed Raman lasers based on diamond crystal

“…The thermal dissipation capacity for many Raman crystals must be taken into account since it impacts markedly on the Raman laser power scaling. When the heat deposited in the Raman crystal is unable to dissipate promptly, the negative thermal effects such as thermal lensing and birefringence will occur, destabilizing the laser resonator and then restricting the laser beam quality, output power and conversion efficiency [42]. The CVD-grown single diamond crystal has been measured to have a record-high thermal conductivity (2000 W/m K), two to three orders of magnitude higher than other conventional Raman crystals, and an extremely low thermal expansion coefficient (1.1 × 10 −6 K −1 ), at least four times lower than other crystals [16,43].…”

Effective diamond deposition on Ti:sapphire with a Cr interlayer via microwave plasma chemical vapor deposition

“…6–8 Meanwhile, thermal issues in the application of high-power lasers are a major concern. 9–11 More attention has been paid to the integration of laser crystals and diamond heat sinks. For example, the direct bonding of a Nd:YAG crystal and a coated diamond crystal was demonstrated to realize a composite laser with a small internal loss.…”