This research was supported in part by the National Science Foundation and by Tektronix, Inc.
Journal of the Optical Society of America B: Optical Physics
Ultrashort laser pulses -- Measurement, Ultrashort laser pulses -- Mathematical models
The output train of pulses from an acousto-optically mode-locked argon-ion laser was studied as a function of the loss modulation frequency for small detunings from the optimum c/2L modulation. A shift away from the optimum frequency by as little as 1 part in 10⁴ was found to produce several strong lower-frequency components that amplitude modulate the mode-locked pulse train. Notably, the strongest subharmonic is a frequency near ƒopt/4. Further detuning results in an irregular, slow (of the order of 10⁵ Hz) amplitude envelope on the pulse train. The homodyne spectrum of this phase of operation represents a progressive filling-in behavior reminiscent of deterministically chaotic systems.
D. L. MacFarlane and Lee W. Casperson, "Pulse-train instabilities in a mode-locked argon laser: experimental studies," J. Opt. Soc. Am. B 4, 1777-1780 (1987).