Gauthier, DJ; Narum, P; Boyd, RW, *Observation of deterministic chaos in a phase-conjugate mirror*,
Physical Review Letters, vol. 58 no. 16
(1987),
pp. 1640-1643 [doi] .
**Abstract:**

*Deterministic chaos in the intensity of the beam produced by a barium titanate self-pumped phase-conjugate mirror has been observed. The correlation exponent of the strange attractor is found to depend on the crystal orientation and to lie within the range 1.2 to 2.4, and the order-two Renyi entropy is found to increase with increasing laser intensity and to be as large as 22 bits/sec. A standard model of self-pumped phase conjugation due to four-wave mixing has been generalized to include time dependence. This model predicts frequency shifts and chaotic behavior for the reflectivity. © 1987 The American Physical Society.*