Gaussian-type breath modes of spatial soliton formed in logarithmically saturable nonlinear media

Using equations governing the variation of the beam size and the curvature of wave front in the logarithmically saturable nonlinear media, the Gaussia n-type breath mode of spatial soliton has been described in detail. With th e aid of a potential method, the positive and negative signs can be assigne d to the first order derivative of the beam size with respect to the propag ation distance. Thus, important parameters of the breath mode, such as the beam size, curvature radius of the wave front, the period, etc., have been calculated.