Efficient high energy frequency-doubled nanosecond Yb-doped 49-core fiber laser

The development of 7x7, Ytterbium-doped, multi-core fiber (MCF) lasers, capable of storing high energy, has led to the generation of a pulse energy above 100 mJ at several kHz repetition rates [1]. This concept currently represents a promising solution for achieving several-hundred millijoule pulses at kilowatt-level average powers. Efficient second and third harmonic conversion of Yb-doped MCF outputs paves the way to high-energy sources operating at high average-powers in the visible and UV regions of the spectrum [2]. For instance, green pulsed lasers are of high interest for numerous applications, including deep-penetration welding of copper [3], and pump sources for titanium sapphire lasers [4].