Hyperbolic Transverse Patterns in Nonlinear Optical Resonators
  We consider a nonlinear optical system in general, and a broad aperture laser in particular in a resonator where the diffraction coefficients are of opposite signs along two transverse directions. The system is described by the hyperbolic Maxwell-Bloch equations, where the spatial coupling is provided by the DAlambert operator rather than by the Laplace operator. We show that this system supports hyperbolic transverse patterns residing on hyperbolas in far field domain, and consisting of stretched vortices in near field domain. These structures are described analytically by normal form analysis, and investigated numerically. 
K. Staliunas, M. Tlidi