PSEUDO-METAL REFLECTION AT THE INTERFACE BETWEEN A LINEAR AND A NONLINEAR MATERIAL

We study theoretically the reflectivity variation of a light wave at t he interface between a linear material and a quadratic nonlinear mater ial, upon simultaneous incidence of a wave at the second harmonic freq uency overlapped with the first one. The presence of the phase-coheren t second harmonic wave results in a phase dependent modification of th e effective complex linear susceptibility of the nonlinear medium. Dep ending on the phase difference between these beams different phenomena occur. Pseudo-metal reflection occurs when there is a net transfer of photons from one wave to the other, whereas modified Fresnel reflecti on takes place when there is no net transfer of photons. (C) 1997 Else vier Science B.V.