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 <sup>4</sup>F<sub>3</sub>/2→<sup>4</sup>I<sub>11/2</sub> transition and at 1.3 μm on the
<sup>4</sup>F<sub>3/2</sub>→4I<sub>13/2</sub> 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.
Laser pulses at 1.06 μm with 2.5-mJ energy and 3.1-MW peak power have been obtained from a composite, all polycrystalline ceramics, passively Q-switched 1.1-at.% Nd:YAG/Cr<sup>4+</sup>:YAG laser that was quasi-continuous-wave pumped with diode lasers. Single-pass frequency doubling with LiB<sub>3</sub>O<sub>5</sub> nonlinear crystal at room temperature yielded green laser pulses at 532 nm with energy of 0.36-mJ and 0.45-MW peak power; the infrared-to-green conversion efficiency was 0.27.
Conference Committee Involvement (1)
International Student Workshop on Laser Applications 2011