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We demonstrate an efficient high power and high brightness yellow-green 556-nm laser generated from second harmonic generation (SHG) of a master oscillator power amplifier (MOPA) laser system at 1112 nm. The oscillator was a pulsed laser diode (LD) pumped and Q-switched Nd:YAG laser at 1112 nm operated at TEM00 mode with an average output power of 35 W, providing 200-μs long macropulses and constituting 700-ns micropulses. The seed laser was amplified by two LD side-pumped Nd:YAG amplifiers and the MOPA system delivered a maximum output power of 78 W. Using a type-I phase-matching lithium triborate nonlinear crystal, the SHG maximum output power of 48 W was obtained at 556 nm with a conversion efficiency as high as 61.5%. The beam quality factor was measured to be M2 = 1.53 and the corresponding brightness was as high as 6.63 × 109 W/cm2·sr.

We demonstrate a high-efficiency high average power vacuum ultraviolet (VUV) 177.3-nm laser with a narrow linewidth generated by second harmonic (SH) generation from a nanosecond (ns) 355-nm laser in the KBe2BO3F2 crystal. The 355-nm pumping source was a frequency-tripled Q-switched 1064-nm Nd:YAG oscillator-amplifier laser system, in which a quartz etalon was used to compress the linewidth of 1064-nm laser. Under a pump power of 5.2 W at 355 nm with a linewidth of 2 pm, a high average power of 146.5 mW at 177.3 nm with a linewidth of ~0.71 pm was obtained, corresponding to an SH conversion efficiency as high as 2.8%. This is, to the best of our knowledge, the highest output power and highest SH conversion efficiency for the ns 177.3-nm lasers. This VUV coherent light can be used as light source for fine precision spectroscopy and semiconductor photolithography owing to its narrow linewidth, high energy resolution, and high average power.