Millijoule pulse energy second harmonic generation with single-stage photonic bandgap rod fiber laser

High power harmonic generation of visible (green) and UV light have been dominated mainly by solid-state lasers but, in recent years, fiber laser based systems have started to challenge them [1]. In most applications, high peak and pulse energies are typically required. Nonlinearities need, therefore, to be minimized and the actual trend is to use large mode area fibers with very large core sizes [2, 3]. Such solution typically requires a master oscillator power amplifier architecture in order to achieve enough average output power or pulse energy without compromising the stability and the quality of the output beam.