Nonlinear optical characterization of spontaneously grown domain structures in SBO crystals

摘要

Spontaneously grown partially ordered domain structures in SBO crystals are characterized via nonlinear diffraction. Domains have the form of sheets lying in cb plane with the domain walls oriented perpendicularly to the a crystallographic axis. The thickness of domains varies in quite wide range. The effective thickness of domains contributing to the nonlinear diffraction is determined from Fourier spectrum of inverse superlattice wave vectors to lie between 180 nm and 8 microns. General properties of spatial Fourier spectrum are reproducible from one growth procedure to another, however, details of spectrum noticeably vary. Enhancement factors for random QPM are calculated and found to be of order of several thousand in the near UV.