The numerical solution of the Maxwell-Bloch equations describing the propagation of a plane monochromatic wave through a saturable absorber shows the appearance of a new kind of reflected wave generated inside the medium. This new phenomenon is described and its physical origin, related to the saturation-induced refractive index changes, is discussed.

• Received 23 July 1985

DOI:https://doi.org/10.1103/PhysRevLett.55.2149