Abstract

The rapid development of ultrafast tunable solid-state lasers has extended to the near infrared with the demonstration of mode-locked Cr⁴⁺:Forsterite' and Cr⁴⁺: YAG lasers.² Previously we reported the first ultrafast Cr⁴⁺:YAG laser, which was actively mode-locked with an acoustooptic modulator to yield 26 ps pulses." Subsequent refinements have reduced the pulse duration to 10 ps and we have also generated ~ 20 ps pulses using synchronous mode-locking. We now report on passive mode-locking of this laser medium. We have observed that, although mode-locking was achieved across almost the full laser tuning range (coating-limited to 1.37–1.58 μm), femtosecond operation was only possible above 1.49 μm. Following a measurement of the intracavity group velocity dispersion (GVD), we attribute this to the deletirious effects of water absorption lines.

© 1994 IEEE