Continuous-wave, 152 W diode-end-pumped Nd:YAG laser operating at 946 nm

Abstract

A high-power continuous-wave (cw) Nd:YAG laser operating at 946 nm by utilizing a quasi-three-level transition is reported. The laser consists of a composite Nd:YAG rod end pumped by a fiber-coupled diode laser and a simple plane-concave cavity. At an incident pump power of 40.2 W, a maximum cw output of 15.2 W at 946 nm is obtained, achieving a slope efficiency of 45%. To the best of our knowledge, this is the highest output at 946 nm ever generated by diode-pumped Nd:YAG lasers. In addition, at an incident pump power of 15.2 W, a 1.25 W blue output at 473 nm is achieved with a simple compact three-element cavity and a type-I lithium triborate (LiB(3)O(5)) crystal as a frequency doubler.

Cryogenically cooled 946nm Nd:YAG laser

“…In recent years the output power and efficiency of the quasi-four-level Nd:YAG laser operating at 946nm has improved significantly [1][2][3]. Notwithstanding, there are three main limitations for power scaling this laser system, firstly it's weak effective stimulated emission cross section, σ e ~4 pm 2 , secondly, the requirement for a high pump-intensity to reach threshold, in part due to reabsorption losses but also the low gain characteristics, which in turn implies a high thermal-load-density and results in significant thermo-optical aberrations, and third, strong competition with the higher-gain four level transition around 1.06 μm.…”

High-Power and Ultra-Efficient Operation of a 946nm Nd:YAG Planar Waveguide Laser

“…In addition, the 4 F 3/2 → 4 I 9/2 transition of Neodymium is attractive as it provides an output wavelength below 1micron, which can be frequency doubled into the blue-green part of the visible spectrum for applications in areas ranging from, underwater sensing and communications, display technologies and information storage, to biological or medical diagnostics. Nd:YAG has been the active host medium of choice for investigation of this transition [1][2][3], due to its excellent thermo-mechanical and thermo-optical properties. In a bulk laser configuration the relatively low gain for this transition, along with the modest reabsorption losses, demand high-brightness pump sources.…”

34 W continuous wave Nd:YAG single crystal fiber laser emitting at 946 nm

“…The highest cw power ever achieved at 946 nm are in the range of the few ten's of watts : 15 W in a bulk end-pumped configuration [3], 25 W with a thin disk laser [4] and 105 W with a planar waveguide [5]. These output power values are far below what can be obtained with Nd:YAG for 1064 nm or 1338 nm four level transitions producing over hundred watts [6,7].…”

“…at maximum pump power) [3]. The thin disk configuration represents a more efficient way to limit the temperature while allowing high pump intensity via multi-pass pumping.…”