Compact, high-power, high-beam-quality quasi-CW microsecond five-pass zigzag slab 1319  nm amplifier

Abstract

We demonstrate a compact, high-power, quasi-continuous-wave (QCW) end-pumped 1319 nm Nd:YAG slab amplifier laser with good beam quality. The laser is based on a QCW pulse Nd:YAG master oscillator and Nd:YAG slab amplifier with multi-pass zigzag architecture. The amplifier operates at a pulse repetition frequency of 500 Hz and pulse width of ∼105 μs, delivering a maximum output power of 51.5 W under absorbed pump power of 217.8 W and corresponding to an extraction efficiency of 14.2%. The beam quality factor is measured to be Mx2=1.61 and My2=1.81 in the orthogonal directions. To the best of our knowledge, this is the first compact, high-power, high-beam-quality QCW Nd:YAG amplifier at 1319 nm based on a multi-pass zigzag slab structure.

210-W, Quasi-Continuous Wave, Nd:YAG InnoSlab Laser at 1319 nm

“…One is the R2 → X1 transition at 1319 nm and the other is the R2 → X3 line at 1338 nm. We can further reduce the reflectivity of the cavity mirrors (M3 and M4) at 1338 nm to suppress its oscillation [15].…”

“…In 2017, Chuan Guo et al obtained a 51.5 W QCW 1319 nm output by using a Nd:YAG slab laser amplifier with the extraction efficiency of 14.2%. The beam quality factors were M 2 x = 1.61 and M 2 y = 1.81 [15]. Although these QCW laser operations have remarkable good beam quality, the average output power needs a further scale.…”

Partially end-pumped 1319 nm Nd:YAG slab laser

“…So that the beam quality deteriorates sharply and the output power is limited, even causing the damage to the gain media. With the slab laser media proposed, theoretical and experimental studies have shown that slab structure can greatly increase heat dissipation and effectively reduce thermal effects, thus achieving high power and high beam quality laser output [9][10][11] . Among various slab lasers, partially end-pumped slab lasers are of particular interest.…”

“…It also allows a lower doping concentration of the gain media, which greatly reduces the thermal gradient and has good thermal management capability to achieve neardiffraction-limited output in the thickness direction. For instance, an end-pumped 1319 nm Nd:YAG slab amplifier laser with output power of 51.5W was obtained in 2017 11 . And an output pulse energy of 8.24 mJ long-pulse quasi continuous wave laser at 1319 nm was realized by the end-pumped slab amplifier in 2020 12 .…”

High-power high-repetition-rate Nd:YAG nanosecond slab laser amplifier

“…Up to now, the Nd:YAG slab crystal structure using Zigzag optical path has been proved to be a method to adjust the average output power and obtain higher optical-optical conversion efficiency [16][17][18] . Because the slab crystal can reduce the thermal gradient inside the crystal by increasing the heat dissipation area of the crystal, and let the laser propagate along the Zigzag path in the temperature gradient direction of the crystal, which can effectively reduce the thermal effect on the output laser [19][20][21][22][23] .…”