We have observed optical second-harmonic generation (SHG) from the (1 0 1)
face of anatase TiO2. The SH intensity From the TiO2 (1 0 1) face in air as
a function of the sample rotation angle around the surface normal gives as
ymmetric patterns for all combinations of input and output polarizations. A
theoretical analysis has shown that the observed optical nonlinearity orig
inates mainly from the surface rather than from the bulk. (C) 2000 Elsevier
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