Cladding waveguides realized in Nd:YAG ceramic by direct femtosecond-laser writing with a helical movement technique

Circular cladding waveguides were realized in a 5.0-mm long, 1.1-at.% Nd:YAG ceramic by direct femtosecond-laser writing using a scheme in which the laser medium is moved on a helical trajectory along its axis and parallel to the writing direction. Laser emission was obtained under the pump with a fiber-coupled diode laser. A 100-μm diameter waveguide delivered laser pulses at 1.06 μm with 3.4-mJ energy for the pump with pulses of 13.1-mJ energy, at 0.30 slope efficiency; laser pulses at 1.3 μm with 1.2-mJ energy were obtained from the same device. Comparison with a waveguide of the same dimension that was inscribed by the classical translation method of the laser medium is made. Efficient integrated lasers based on cladding waveguides that are pumped by fiber-coupled diode lasers could be realized by this writing method.