Demonstration of the Spectral Beam Combining in a Yb:YAG Slab Laser Resonator

We propose and experimentally demonstrate a novel spectral beam combing (SBC) method based on a single slab laser cavity. By establishing the quasi-three-level oscillator model of Yb:YAG crystal, the output characteristics and gain bandwidth of Yb:YAG crystal are investigated theoretically on the basis of the above theoretical model. In a proof-of-principle experiment, the SBC of seven beamlets in a wide-emission-spectrum Yb:YAG slab is realized with an architecture of 7 beamlets which are generated by seven pairs of mini-mirrors and mini-lens, a transform lens, and a multi-layer dielectric grating. Here, a maximum output power of 241 W is achieved, with a 4.1 horizontal beam quality (HBQ) and the output spectrum range spans from
$1029.0~\sim ~1031.5$
nm. To the best of our knowledge, this is the first SBC demonstration of solid-state laser based a single slab.