LD-pumped gas-cooled multislab Nd:glass laser amplification to joule level

Wenfa Huang,Wei Fan,Xuechun Li,Jiangfeng Wang,Tingrui Huang,Xinghua Lu,Jiangtao Guo

doi:10.1017/hpl.2018.7

Abstract

We demonstrate a laser diode end-pumped helium gas-cooled multislab Nd:glass laser amplifier. The design and thermal management of the proposed laser amplifier are discussed. The thermally induced wavefront aberration of the slabs was also measured and compared with simulation results. A small-signal single-pass longitudinal gain of 1.8 was measured with a pump energy of 7.3 J. With an injected seed energy of 0.6 mJ, the output energy from the amplifier reached 0.5 J at 0.2 Hz and 0.43 J at 0.5 Hz in a multipass extraction geometry, thus demonstrating the feasibility of diode-pumped, high-energy lasers with direct gas cooling.

Highlights

Over the recent decades, diode-pumped solid-state lasers (DPSSLs) have attracted much attention due to their many advantages, which include high overall efficiency, low thermal load, compactness
Gas-cooled multislab designs are widely used both in modern and older high-energy DPSSL systems, including HAPLS and Mercury at the Lawrence Livermore National Laboratory in USA[4, 5], DiPOLE at the RutherfordAppleton Laboratory in the United Kingdom[6], and PEnELOPE at the Helmholtz-Zentrum Dresden-Rossendorf research center in Germany[7]. Most of these laser projects are developing Yb3+-doped gain-medium-based concepts for 100 J/10 Hz DPSSL amplifiers that could potentially be scaled to the kJ regime, and which will extend to the Correspondence to: W
The main reason for this discrepancy was traced to the divergence of the pump beam when propagating through the Nd:glass slabs, this will cause poor seed/pump matching lead to less efficient extraction, and the residual thermal load became greater in the slabs resulting in higher thermally induced wavefront aberration

Summary

Introduction

Diode-pumped solid-state lasers (DPSSLs) have attracted much attention due to their many advantages, which include high overall efficiency, low thermal load, compactness. In order to achieve high energy and high repetition rate, the choices of amplifier geometry and thermal management are important aspects of DPSSLs to consider. We demonstrated a laser-diode-pumped gascooled multislab laser amplifier. We selected Nd:phosphate glass as the gain medium owing to its sufficient storage lifetime (∼330 μs), high saturation fluence (∼5 J/cm2) to store energy, and high quality. Compared to Yb-doped materials, Nd:phosphate glass meets the requirements for efficient high-average-power operation, while possessing an easy-to-realize large aperture[14]. The design and thermal management of the proposed multislab Nd:phosphate glass laser amplifier were discussed. Output energies of 0.5 J at 0.2 Hz and 0.43 J at 0.5 Hz were achieved

Design and experimental setup

Experimental results and discussion

Findings

Conclusion