High-efficiency, high-average-power, CW Yb:YAG zigzag slab master oscillator power amplifier at room temperature

Abstract

We demonstrate a high-efficiency, high-average-power, CW master oscillator power amplifier based on a conduction-cooled, end-pumped Yb:YAG slab architecture at room temperature (RT). Firstly, the CW amplification property is theoretically analyzed based on the kinetics model for Yb:YAG. To realize high-efficiency laser amplification extraction for RT Yb:YAG, not only intense pump but also a high-power seed laser is of great importance. Experimentally, a composite Yb:YAG crystal slab with three doped and two un-doped segments symmetrically is employed as the gain medium, which is end-pumped by two high-power, 940-nm diode lasers. A high-power, narrow-spectral-width, 1030-nm fiber seed laser then double passes the composite slab to realize efficient power amplification. For 0.8-kW seed input, maximum output power of 3.54 kW is obtained at 6.7 kW of pump power, with the optical conversion efficiency of 41% and the highest slope efficiency of 59%. To the best of our knowledge, this is the highest power and efficiency reported for Yb:YAG lasing at RT except thin-disk lasers.

Efficient, diode-pumped, high-power (>300W) cryogenic Yb:YLF laser with broad-tunability (995-10205 nm): investigation of E//a-axis for lasing

“…Moreover, the simple energy level diagram and lack of undesired energy transfer process such as excited state absorption and Auger upconversion, results in almost quantum limited emission efficiency and minimizes the thermal load on the Yb:YAG crystals. The material also posses quite strong thermo-mechanical parameters, enabling application of different laser geometries such as usage of rod type crystals with diffusion-bonded un-doped end-cap sections [8], complex architectures with flexibility of ceramic growth [9], inno-slab or zig-zag slab geometry [10,11], crystal fiber approach [9], and finally thin-disk concept [1,3]. These novel laser architectures already enabled kW level power levels from Yb:YAG laser/amplifier systems operating at room temperature.…”

40 W high beam quality Tm:YLF InnoSlab amplifier

“…The InnoSlab structurebased slab laser amplifier has gained popularity as a research topic both domestically and internationally in recent years. Many laser crystals such as Nd:YAG [9], Yb:YAG [7,10], and Ho:YLF [11,12] are used to achieve high average power and high beam quality laser output such as ns, ps, and fs amplifier.…”

Crystal growth and photoluminescence spectra properties of (YbxNdySc1−x−y)2SiO5 laser crystal

“…Trivalent ytterbium (Yb 3+ ) doped materials have demonstrated significant potential for application in ultrafast lasers, high-power lasers and amplifier systems. Yb 3+ ions possess two electronic states, ground state 2 F 7/2 and excited state 2 F 5/2 , that retain the advantages of low quantum defects, a long fluorescence lifetime and a high conversion efficiency [1][2][3][4][5]. Yb 3+ ions doped Sc 2 SiO 5 (Yb 3+ :Sc 2 SiO 5 ) has shown the capability of achieving a stable mode-locked ultrafast laser with a pulse duration of 71 fs at a repetition rate of 89 MHz [6].…”