Abstract

A Nd:YAG laser with an intracavity frequency doubling crystal displays irregular intensity fluctuations for certain ranges of operating parameters.¹,² Analysis of the laser system shows that these fluctuations are chaotic in nature, and that it is possible to operate the laser stably in selected parameter regimes.²,³ It has also been shown experimentally that dynamical control of such a laser system is possible, and that a variety of periodic waveforms as well as the unstable steady state can be stabilized through an appropriate feedback technique called occasional proportional control.⁴,⁵ In this technique, tiny kicks are given to the pump excitation, that depend in amplitude on the difference of the output intensity from a chosen reference level, and with a period related to the relaxation oscillation period. The laser may be maintained in a stabilized steady state over a wide range of pumping if a tracking procedure is used that makes suitable changes in the control circuit parameters as the pump level is altered.

© 1993 Optical Society of America