Role of nanostructure on the optical waveguiding properties of epitaxial LiNbO3 films

• Published in: Journal of physics. D, Applied physics Vol. 42; no. 14; pp. 145403 - 145403 (10)
• Main Authors: Boulle, A, Kilburger, S, Di Bin, P, Millon, E, Di Bin, C, Guinebretière, R, Bessaudou, A
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 21.07.2009; Institute of Physics
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Optical elements, devices, and systems; Optical waveguides and coupleurs; Optics; Physics; Wave optics; Wave propagation, transmission and absorption; Non linear material; Ternary compounds; Roughness; Measuring methods; Pulsed laser deposition; XRD; Nanostructures; Layer thickness; Optical waveguides; Optical losses; Monocrystals; Electromagnetic wave propagation; Intensity distribution; Strains; Optical properties; X radiation; Optical materials; Lithium Niobates; Nanostructured materials; Nanocrystal
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/42/14/145403

High-quality LiNbO3 (LN) epitaxial films have been grown on (0 0 1)Al2O3 substrates by pulsed laser deposition. The deposition conditions have been optimized using experimental designs to promote the growth of highly (0 0 1)-oriented, phase pure and light-guiding LN films. The structural and nanostructural properties have been investigated by x-ray diffraction reciprocal space mapping and the guiding properties have been investigated by m-line spectroscopy and measurements of the light propagation losses. In particular it is shown that the film composition, the state of strain, the film thickness, the film roughness, the lateral extension of the crystallites building up the film as well as the mosaicity can be determined by a careful examination of the x-ray reciprocal space maps associated with simulation of the diffracted intensity distribution in reciprocal space. The guiding properties have been correlated with the nanostructural properties of the films: whereas light guiding has been clearly observed in single-crystal-like films, the existence of a mosaic structure, made of nanocrystalline domains, is shown to be detrimental to the guiding properties.