Different crises, i.e., abrupt qualitative changes in the properties of attractors, have been observed in a C${\mathrm{O}}_2$ laser with internal modulation. They are shown to be related to crossing between a stable or unstable periodic cycle and the strange attractor resulting from the period-doubling cascade observed at low modulation levels. Depending on the operating conditions, boundary and interior crises have been observed.

• Received 16 July 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.2657