Macroscopic quantum fluctuations in noise-sustained optical patterns

We investigate quantum effects in pattern-formation for a degenerate
optical parametric oscillator with walk-off. This device has a
convective regime in which macroscopic patterns are both initiated and
sustained by quantum noise. Familiar methods based on linearization
about a pseudo-classical field fail in this regime and new approaches
are required. We employ a method in which the pump field is treated
as a c-number variable but is driven by the c-number representation
of the quantum sub-harmonic signal field. This allows us to include the
effects of the fluctuations in the signal on the pump, which in turn act
back on the signal. We find that the non-classical effects, in the form of squeezing,
survive just above the threshold of the convective regime. Further above threshold
the macroscopic quantum noise suppresses these effects.



See also the erratum Phys. Rev. A 65, 049901 (2002)