Single-frequency, injection-seeded Q-switched Ho:YAG ceramic laser pumped by a 1.91μm fiber-coupled LD.

A 2090 nm injection-seeded Q-switched Ho:YAG ceramic laser pumped by a 1.91 μm fiber-coupled LD is demonstrated in this paper. Single-frequency operation of Q-switched Ho:YAG ceramic laser is achieved by injection seeding technique. The maximum output energy of the single-frequency Q-switched Ho:YAG ceramic laser is 14.76 mJ, with a pulse width of 121.6 ns and a repetition rate of 200 Hz. The half-width of the pulse spectrum measured by heterodyne technique is 3.84 MHz. The fluctuation of the center frequency of the pulsed laser is 1.49 MHz (RMS) in 1 hour. As far as we know, this is the first time to report a single-frequency, injection-seeded Ho:YAG ceramic pulsed laser.