High-Power, High-Purity HG_0n Hermite-Gaussian Laser Beam Generation in Cascaded Large Aspect Ratio Slabs

High-power, high-purity, nanosecond (ns) one-dimensional HG(0n) laser beams are proposed and demonstrated by using Nd:YAG cascaded slabs with a large aspect ratio. The HG(0n) laser beams are generated by adjusting the pump distribution, the intracavity apertures, and the tilt angle of the output coupler (OC). By controlling the gain and loss of HG(0n) modes of different orders, the high-purity, one-dimensional, high-order HG(0n) laser beams with orders 1 to 9 (HG(01) to HG(09)) are produced, and their beam quality factors M-2 align well with the theoretical predictions. Meanwhile, the large aspect ratio slab provides an ideal amplifier for the strip-shaped HG(0n) laser beams, and further power scaling is achieved by seeding the generated HG(0n) laser beams into an amplifier with an identical slab module. For the HG(09) mode, the average power is amplified from 289 mW to 4.73 W with 294 ns pulse width, corresponding to a peak power of 32 kW. Moreover, above 5 W average power is achieved for all HG(01) to HG(08) modes. Hopefully, this scheme provides a solution for high-power and high-purity HG(0n) laser beam generation based on the slab-shaped configuration.