Abstract

A strontium barium nlobate (SBN) crystal inserted into a multiline argon-ion laser beam produces high-interisity multicolored conical diffraction rings or a rainbow pattern and self-pumps at several different wavelengths simultaneously. Both observations are new and differ substantially from previous work. For example, unlike previous reports¹ of conical diffraction, the polarization of the rainbow pattern which we observe is the same as that of the incident beam. Moreover, the physical mechanism for the formation of the rainbow is cooperation between gratings written at different wavelendths as opposed to phase matching between ordinary and extraordinary light in the crystal. Our observation of simultaneous self-pump phase conjugation at several different wavelengths was carried out with no external pumping beams and no external mirrors, as have been employed by other investigators.²

© 1988 Optical Society of America