Pulsed-laser deposition growth of SBN and correlation study of structure and optical properties

Abstract

Strontium barium niobate (Sr x Ba 1-x Nb 2 O 6 ) thin films were grown by PLD and characterized as to their structure, composition, and both linear and nonlinear optical properties. Attempted composition of very nearly x=0.61 was achieved, as shown within experimental error of RBS and PIXE techniques. Films were deposited on MgO (001) and fused silica substrates at a range of growth rates, while keeping other factors constant. Films with excellent texture, and oriented with the c-axis normal to the substrate surface where obtained on the MgO substrates. Films grown on fused silica showed a range of structures, from essentially amorphous to well oriented, again with c-axis normal to the substrate surface. The absorption edge of the films was determined to be substantially blue-shifted in comparison with bulk material. This effect appears to correlate with film microstructure, with more disordered films grown on glass showing the largest shifts. Degenerate four-wave-mixing techniques were used to study the nonlinear optical response of the amorphous films. A considerable enhancement, by 2 orders of magnitude, of the third order nonlinear susceptibility X (3) in transverse alignment was found to occur with respect to bulk values.