Abstract

We study pattern formation that is due to modulational instability of noncollinear counterpropagating beams. Angular misalignment of the pumps over a broad range leads to the generation of lines oriented perpendicular to the plane of the pump beams. A theoretical expression for the angular separation of the lines is in close agreement with observations. Outside this range, for both small and large misalignments, we observe squeezed hexagonal patterns.

© 1997 Optical Society of America

Spontaneous hexagon formation in photorefractive crystal with a single pump wave

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