DARK SPATIAL SOLITONS OF THE TM-TYPE

The existence of dark spatial solitons of the TM type is examined. This type of two-dimensional solitary wave is found to exist in the self-defocusing nonlinear medium of a Kerr-law type in the range of the wave effective index n(eff) from 0.82n0 to n0 of the linear refractive index of the medium. This contrasts with dark spatial solitons of the TE type, which exist in the range of n(eff) from 0 to n0. The longitudinal component is shown to play a key role leading to this distinction. The comparison between TM and TE solitons is also made on other aspects. For example, the field profile of the TM soliton is shown to vary with the wave effective index, whereas that of the TE soliton is characterized by the hyperbolic tangent function, independent of n(eff).