Holographic scattering processes in photorefractive KTa1-xNbxO3 (KTN) cryst
als are investigated resulting from the simultaneous action of one or two p
ump beams. Different scattering patterns are observed on a screen behind th
e crystal. A comparison between the intensity distribution of the scattered
light and the consequences of certain phase-matching conditions permits th
e identification of the processes involved. (C) 1999 Elsevier Science B.V.
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