20-W Ultraviolet Femtosecond GHz Burst Laser

We present a high-power femtosecond GHz burst laser with nonlinear frequency conversion to the ultraviolet spectral region. An average power as high as 20-W at 343nm wavelength has been obtained after third harmonic generation of a 100-W, 480-fs GHz burst mode femtosecond laser at 1030nm. This is to our knowledge the first demonstration of a high-power ultraviolet femtosecond laser with GHz bursts. GHz femtosecond lasers have recently revealed significant interest for micro-machining applications, in particular by showing substantially increased ablation efficiencies on different materials [1, 2]. Frequency conversion to the ultraviolet spectral region is highly interesting for spatial and chemical selectivity in multi-material or multi-layer material processing, especially for materials containing organic components. Our high-power UV femtosecond GHz burst laser is therefore promising for high efficiency and high-quality laser processing of polymer-based materials with low heat affected zones.