82  kW high beam quality quasi-continuous-wave face-pumped Nd:YAG slab amplifier

Abstract

An 8 kW level quasi-continuous-wave (QCW) face-pumped 1064 nm slab laser with high beam quality was developed by a master oscillator power amplifier (MOPA) system. A single-mode fiber seed laser was amplified by two-stage single-pass Nd:YAG rod preamplifiers and four face-pumped Nd:YAG slab amplifiers. The slab amplifiers were well designed with uniform pumping and uniform cooling for well-distributed thermal and stress. A dynamically feedbacked optical aberration compensation device was employed to correct low-order optical aberration, and the residue high-order optical aberration was corrected by an adaptive optics system. The QCW MOPA delivered up to an average power of 8.2 kW with a pulse duration of 200 μs at a repetition rate of 400 Hz. The beam quality factor was measured to be β=3.5.

Actively compensation of low order aberrations by refractive shaping system for high power slab lasers

“…With the combination of the refractive shaping system and an AO system, a 10 kW level Nd:YAG slab amplifier with good beam quality was developed and was reported in Ref. [13].…”

“…Results show that for an input laser beam with large low order aberration, the wavefront aberration can be reduced about two order of magnitude and the experimental data are excellent agreement with the theoretical simulation. The refractive shaping system has been successfully used in 10 kW level quasi-continuous-wave (QCW) master oscillator power amplifier (MOPA) Nd:YAG slab laser for low order aberrations compensation [13], which bridged the gap between large magnitude low order aberrations and finite stroke limit of AO.…”

High power and high beam quality quasi-continuous-wave pumped slab laser

“…High-power quasi-continuous-wave pumped slab lasers are widely used in various fields, such as laser welding, laser paint removal, laser medicine, laser cutting and so on [1][2][3][4][5]. In recent years, quasi-continuous semiconductor lasers have gradually promoted the rapid development of high-power quasi-continuous all-solid-state lasers, which have the advantages of high peak power and high duty cycle [6,8].…”

The 10 kW Level High Brightness Face-Pumped Slab Nd:YAG Amplifier with a Hybrid Cooling System

“…[4] The brightness achieved in this work was enhanced over more four times higher than the previous best result (8.2 kW output power and 𝛽 = 3.5). [9] The lower right inset of Fig. 7 shows the typical pulse trains, and the pulse width was found to be about 150 µs with a repetition rate of 700 Hz.…”

“…[8] In 2015, Chen et al developed a master oscillator power amplifier (MOPA) system with a face-pumped Nd:YAG crystal slab, which created a maximum 8.2 kW of output power, operating at a repetition rate of 400 Hz with a pulse duration of 200 µs and beam quality factor of 𝛽 = 3.5. [9] To date, the face-pumped slab schemes for high power system are mainly using the forced convection cooling systems, i.e., the coolant flows over both the top and bottom large faces of the slab symmetrically. [8−11] However, the heat transfer capacity is limited by the heat transfer coefficient at the interface of coolant and slab, which imposes restrictions on power scaling potential of the laser gain module.…”