Experimental investigation of the collision of Feigenbaum cascades in lasers

We have experimentally checked on a CO₂ laser with modulated losses the universality law set by Oppo and Politi [Phys. Rev. A 30, 435 (1984)] for the collision of Feigenbaum cascades. The scaling properties of the first three period-doubling bifurcations are in good agreement with their predictions, but fast passage effects and a limited signal-to-noise ratio impose severe limits on precise quantitative measurements.