A theoretical analysis of the diffracting effects produced by ASW on light beams contained on the sagittal plane of the wave is presented. The separate contributions have been explicitly studied, produced by periodical changes of the refractive index and by corrugation of the surface in cases ofx‐ andy‐cut crystalline quartz andy‐cut LiNbO3for both states of polarization of the incident light. In all cases analyzed, measurements of light‐deflection efficiency have been performed as a function of the angle of incidence in light‐transmission experiments.