Cladding waveguides have been realized in Nd:YAG by direct writing with a femtosecond-laser beam. A classical
method that inscribes many tracks around the waveguide circumference with step-by-step translations of the laser
medium, and a new technique in which the laser medium is moved on a helical trajectory and that delivers waveguides
with well-defined walls were employed. Laser emission on the 1.06 μm 4F3/2→4I11/2 transition and at 1.3 μm on the
4F3/2→4I13/2 line was obtained under the pump with a fiber-coupled diode laser. Thus, laser pulses at 1.06 μm with energy
of 1.3 mJ for the pump at 807 nm with pulses of 12.5-mJ energy were recorded from a circular waveguide of 100-μm
diameter that was inscribed in a 5-mm long, 0.7-at.% Nd:YAG single crystal by the classical translation technique. A
similar waveguide that was realized in a 5-mm long, 1.1-at.% Nd:YAG ceramic increased the 1.06-μm laser pulse energy
to 2.15 mJ for the pump pulses of 13.1-mJ energy. Furthermore, a circular waveguide of 100-μm diameter that was
inscribed in the Nd:YAG ceramic by the helical-movement method yielded pulses at 1.06 μm with increased maximum
energy of 3.2 mJ; the overall optical-to-optical efficiency was 0.24, and the laser operated with a slope efficiency of 0.29.
The same device outputted laser pulses at 1.3 μm with energy of 1.15 mJ.