Spiraling elliptic solitons in nonlocal nonlinear media without anisotropy

Abstract

The spatial optical solitons with ellipse-shaped spots have generally been considered to be a result of either linear or nonlinear anisotropy. We investigate a class of spiraling elliptic solitons in nonlocal nonlinear media without both linear and nonlinear anisotropy. The spiraling elliptic solitons carry the orbital angular momentum (OAM), which plays a key role in the formation of such solitons, and are stable for any degree of nonlocality except the local case if the response function is Gaussian. During the propagation of such solitons, the rate of decay of the OAM is extremely low. The formation of such solitons can be attributed to effective anisotropic diffraction (linear anisotropy) resulting from the OAM. Our variational analytical result is confirmed by direct numerical simulation of the nonlocal nonlinear Schr\odinger equation.