Observation of coherent transients by use of current switching of a semiconductor diode laser

Abstract

We have observed optical free induction decay on the 3H6(1) → 3H4(1) transition of Tm3+ ions in LaF3, using an external-cavity diode laser. The diode-laser frequency was switched by the application of a current step, and the resulting transient was detected by heterodyne beating with the laser at its new frequency. This provides a. simple new way to measure coherent transients. The beat note shows a frequency chirp that gives a real-time measure of the diode-laser frequency. This result is attributed to changes in the laser lattice temperature on the microsecond time scale. © 1997 Optical Society of America.