Superfluid state of coherent light in nonlinear waveguides

Ze Cheng

F. Baboux

Ze Cheng

We study the thermodynamic properties of coherent photons in self-focusing nonlinear waveguides. The equation of the superfluid state of photons has been derived. There is a transition temperature [Formula: see text], above which the photon gas is in the coherent state, but below which the photon gas is in the superfluid state. At [Formula: see text], the photon system undergoes a first-order phase transition from the coherent to the superfluid state. To determine the fugacity [Formula: see text] and the transition temperature [Formula: see text] of the photon gas, we numerically solve the equation of the superfluid state of photons. The fugacity [Formula: see text] is a monotonically decreasing function of temperature [Formula: see text] and light intensity [Formula: see text]. The transition temperature [Formula: see text] is a monotonically decreasing function of light intensity [Formula: see text].

Omar Boughdad

Jan Peřina

We investigate both codirectional and contradirectional nonlinear couplers composed of two nonlinear waveguides operating by second harmonic generation. We take into account possible mismatches inside the waveguides and between them. Quantum statistical characteristics, such as photon number distribution, its factorial moments, quadrature and integrated intensity vari- ances and quadrature uncertainty product can demonstrate effects of transmission of light between waveguides. Incident beams can be assumed to be coherent, squeezed and mixed with external noise. Second harmonic modes are assumed to be pumped with strong coherent beams. Nonclassical behavior of beams generated by the nonlinear waveguides can be transferred between them and controlled by linear and nonlinear mismatches. In the contradirectional regime of propagation asymptotic nonclassical states can be generated.

Lene Vestergaard Hau