Laser emission from buried depressed-cladding waveguides inscribed in Nd:YAG ceramics by picosecond-laser beam writing

Buried, depressed-cladding waveguides were inscribed in a 1.1-at.% Nd:YAG ceramic by direct writing with a picosecond-laser beam. Laser emission performances were investigated under the pump with fiber-coupled diode lasers. For quasi-continuous-wave pumping, a circular waveguide with 100 μm diameter yielded laser pulses at 1.06 μm with 2.4 mJ energy for 12.8 mJ pump pulse energy at 807 nm (corresponding to an overall optical-to-optical efficiency of 0.19); the slope efficiency was 0.22. Continuous-wave output power of 0.35 W at 1.06 μm with overall optical-to-optical efficiency of 0.09 was obtained from the same waveguide; the slope efficiency amounted to 0.12. Furthermore, the circular waveguide yielded laser pulses at 1.32 μm with 0.4 mJ energy (at an overall optical-to-optical efficiency of 0.03); the slope efficiency amounted to 0.03.