Theoretical Research of PR SEW at the LiNbO 3 -Air Interface

The nonlinear photorefractive surface electromagnetic waves (PR SEW) based on the photovoltaic (PV) effect at the LiNbO 3-air interface is analyzed theoretically for the first time to our known. We show theoretically that when an extraordinarily polarized signal beam and an ordinarily polarized background beam are launched onto the interface between air and LiNbO 3 crystal whose ?311 > ?333, the refractive-index change ?n (induced by the PV effect) reverses its polarity. We have solved the equations numerically and the stationary solution of the signal beam is obtained, which decays from the crystal-air interface to the bulk of the crystal.