Heterodyne measurements of the field of Lorenz-type far-infrared-laser intensity pulsations reveal two different kinds of chaotic attractors. At high pressure, a symmetric attractor is found (two saddle foci), representing (heteroclinic) Lorenz-type chaos. At lower pressure, in accordance with theoretical modeling, an asymmetric attractor (one saddle focus) is found, generating (homoclinic) Roessler- or Shilnikov-type chaos. Detuned lasers exhibit phase switches smaller than $\pi$ as predicted.

• Received 31 May 1988

DOI:https://doi.org/10.1103/PhysRevLett.61.1587