Organic thin films are ubiquitous in modern science and technology. However their relatively higher propensity to beam induced damage relative to inorganic thin films, the need for molecular information, and the need to study these materials in situ mean that the vacuum based particle spectroscopies are not particularly well suited to their study. They can however be studied using the thin films themselves as the active layers of integrated optical structures. When excited with a waveguide eigenmode, for which the electric field amplitude distribution in space is well defined, the spectroscopy and optics of the structure necessarily contain information about how the chemical make-up of the film changes with depth. In optical depth profiling experiments the complete set of waveguide eigenmodes is used to excite Raman scattering from film constituents. The spectroscopic data are then used to invert a series of Fredholm integral equations of the first kind, thus yielding the molecular distribution in space. In another set of experiments the dynamics of small molecule uptake are monitored by examining the change in the resonant eigenmodes after introduction of a solution to the surface of the film.

Date Published: 19 January 1989
PDF: 8 pages
Proc. SPIE 0990, Chemical, Biochemical, and Environmental Applications of Fibers, (19 January 1989); doi: 10.1117/12.959984

Published in SPIE Proceedings Vol. 0990:
Chemical, Biochemical, and Environmental Applications of Fibers
Robert A. Lieberman; Marek T. Wlodarczyk, Editor(s)