Abstract

The paper considers the theory of stimulated Mandelshtam-Brillouin scattering (SMBS) in running conditions, i.e., with the length of the scattering medium significantly exceeding the spatial length of the pump pulse. In such conditions the pump pulse runs through the medium, and stimulated scattering of the pump wave into the Stokes wave takes place from different layers of the medium.¹ An investigation of the process is carried out for both homogeneous and inhomogeneous media. The strict expressions are obtained from the Green function and the Stokes wave field. The spectrum and the coefficient of increment of the Stokes irradiation are analyzed. It has been shown that the effect of modulation of the Stokes irradiation frequency takes place due to stationary periodic inhomogeneities of the refractive index in a medium. This effect occurs also from periodic alterations of the value of light fiber cross-section. A computer simulation of the process of running SMBS confirms the theory. Practical possibilities are discussed concerning the usage of running SMBS for remote probing of a medium’s inhomogeneities and for some other applications.

© 1991 Optical Society of America