PHASE-SENSITIVE SIGNAL AMPLIFICATION AND SQUEEZING NEAR PERIOD-DOUBLING BIFURCATION IN A CO2-LASER

The effect of the phase of a perturbation signal at frequency f/2 on t he laser response has been investigated in a CO2 laser with losses mod ulated at frequency f near a period-doubling bifurcation, Phase-sensit ive signal amplification and classical squeezing have been detected an d studied both theoretically and experimentally. We have found that ph ase-sensitive squeezing exists only below the bifurcation point. The s queezing width decreases linearly with increasing bifurcation paramete r and the squeezing depth increases with bifurcation parameter being 3 0% at the bifurcation point for the parameters used. We interpret the observed experimental results for zero phase on the basis of the exist ence of multistability of periodic solutions with the same frequency f /2 as the perturbation signal.