Yb:KYW planar waveguide laser Q-switched by evanescent-field interaction with carbon nanotubes.

We report Q-switched operation of a planar waveguide laser by evanescent-field interaction with single-walled carbon nanotubes deposited on top of the waveguide. The saturable-absorber-integrated gain medium, which operates based on evanescent-field interaction, enables the realization of a diode-pumped 2.5-cm-long Q-switched Yb:KYW waveguide laser emitting at 1030 nm. With such a compact cavity design, we achieve maximum output powers of up to 30 mW, corresponding to a single-pulse energy of 124 nJ, at 241 kHz repetition rate. The shortest pulse duration of 433 ns is generated at a repetition rate of 231 kHz.