Effect of beam shape transformation in Bragg transmission of bounded laser beams through the periodically corrugated dielectric waveguide

Beam anomalies in transmission of Gaussian light beams through the dielectric waveguide with incorporated periodic relief grating are investigated theoretically. The anomalies take place near the critical incidence, determined by Bragg condition, when the divergency of the incident beam is of the order or greater than the angular width of Bragg resonance. They manifest themselves as macroscopic transformation of transmitted beam shape and can be accompanied by multiple oscillations of intensity in the beam spot. The transformation of the beam shape is stipulated by interference effect due to the resonant excitation of guided modes in the waveguide by incident bounded light beam and subsequent rescattering of these modes in the direction of transmitted beam propagation.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.