Abstract

The CO₂ laser with a saturable absorber gas has been studied by analysis of its pulse time series [2,1]. The dynamics with periodic-chaotic-periodic sequences of bifurcations characterize the homoclinic nature of the system [1]. Sistematic bifurcation diagrams, however, were never compared with the models. Using a derivative followed by a zero crossing trigger circuit in the 10 – 100 KHz range the peak value of the Q-switching pulses of a CO₂ laser with SF₆, as a saturable absorber, was collected. The system is capable of simultaneous acquisitions of time series and/or peak signal with control parameter variation, as shown in figures 1 and 2. The laser was tuned over 80MHz and a remarkable symetrical bifurcation diagram was obtained in the P(18) line. The electronic delay was 1microsecond, making the leading peak to apear underestimated. Diagrams obtained from analog circuit simulation of the three-two level model [3] completely agree with Fig. 2. Quantitative measurements for the control parameter values where the bifurcations take place will further test that model.

© 1998 IEEE