Electron diffraction studies of Langmuir-Blodgett film structures with potential for optical applications

Abstract

The Langmuir-Blodgett film technique is currently being researched as a deposition process for many optical applications. The performance of these coatings is dependent on both the quality of deposition and the film structure. A structural investigation, using transmission electron diffraction and microscopy, on materials with potential for second harmonic generation and optical data storage is reported on this paper. Transmission electron diffraction patterns are presented for an optically non- linear stilbene derivative. Results indicate that monolayer quality is good but for the formation of multilayers causes the film quality to deteriorate. The technique of alternating this material with tricosanoic acid has improved deposition, and electron microscopy has been used to indicate this. High quality transmission electron diffraction patterns of tricosanoic acid are interpreted in terms of a pseudo- hexagonal packing arrangement with a grain size of approximately 5 μm. Organic dyes which absorb in the near-IR have also been studied. These have potential for use in ablative optical hole burning for optical data storage. Electron diffraction results are presented, showing good structure, with a grain size suitable for this application.