Femtosecond laser direct writing of depressed cladding waveguides in Nd:YAG with ear-like structures: fabrication and laser generation

Low-loss depressed cladding waveguide architecture is highly attractive for improving the laser performance of waveguide lasers. We report on the design and fabrication of the ear-like waveguide structures formed by a set of parallel tracks in neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal via femtosecond laser writing. The obtained ear-like waveguides are with more symmetric mode profiles and lower losses by systematically comparing the guiding properties of two kinds of normal cladding waveguide. Efficient waveguide lasers are realized based on the designed structure in both continuous wave and pulsed regimes. Combined the high-gain from cladding waveguide and special ear-like structure, a passively fundamentally Q-switched laser with the narrow pulse width and the high repetition rate has been obtained by using tin diselenide (SnSe2) as saturable absorber. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

A low-loss depressed cladding waveguide architecture was designed and fabricated in neodymium-doped yttrium aluminum garnet crystal, with ear-like waveguide structures formed by femtosecond laser writing. These structures showed more symmetric mode profiles and lower losses, leading to efficient waveguide lasers in both continuous wave and pulsed regimes, as well as a passively fundamentally Q-switched laser with narrow pulse width and high repetition rate.