Phase instability and intensity squeezing in lasers with two-photon saturable absorbers
P G Fernandez, Luigi A. Lugiato, Francisco Javier Bermejo · Quantum Optics Journal of the European Optical Society Part B · 1991
It is shown that a laser with a two-photon saturable absorber exhibits a phase instability similar to that of two-photon optical bistability. The authors calculate the spectrum of the intensity fluctuations in the output field under conditions of exact resonance between the amplifier and the absorber. In the bad-cavity limit the relevant part of the spectrum assumes a simple Lorentzian form; as the phase-instability threshold is approached, the reduction of quantum noise becomes perfect for small frequencies.