5.9 GHz graphene based q-switched modelocked mid-infrared monolithic waveguide laser

A high repetition rate Q-switched modelocked similar to 2.1 mu m monolithic waveguide laser is reported. Ultrafast laser inscription is used to fabricate 3D depressed cladding channel waveguides in holmium doped yttrium aluminium garnet. This results in a transversely single mode waveguide laser. With the use of a graphene based saturable output coupler, Q-switched modelocking was achieved with a pulse repetition frequency of 5.9 GHz and up to 170 mW of average output power. This first demonstration of multi-GHz repetition rate operation from a Ho3+:YAG laser provides a compact and convenient source for a number of applications. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.