Multimode nonclassical light generation through the optical-parametric-oscillator threshold
Bénoît Chalopin, Francesco Scazza, Claude Fabre, Nicolas Treps · Physical Review A · 2010
We show that an optical parametric oscillator which is simultaneously resonant for several modes, either spatial or temporal, generates both below and above threshold a multimode nonclassical state of light consisting of squeezed vacuum states in all the nonoscillating modes. We confirm this prediction by an experiment dealing with the degenerate TEM${}_{01}$ and TEM${}_{10}$ modes. We show the conservation of nonclassical properties when the threshold is crossed. The experiment is made possible by the implementation of a new method to lock the relative phase of the pump and the injected beam.