Vector dark spatial solitons

The dark spatial solution of TM type is shown to exist in a uniform selfdefocusing nonlinear medium in the range of the beam effective index n_eff from 0.82n₀ to n₀ of the linear refractive index of the medium. This contrasts with the dark spatial soliton of TE type which exists over all the possible values of n_eff ranging from 0 to n₀. The field profile of this TM dark wave is also found to depend on the beam effective index, deviating from the hyperbolic tanh function of TE type with decreasing n_eff.