title: Elastic behaviour of a nanocomposite thin film undergoing significant strains.
abstract: For nearly a century, dielectric materials have been used to produce thin film filters capable of precisely modifying electromagnetic wave interactions at material boundaries. Minimizing visible reflections from optical elements is the most mature use of these techniques, but modern applications often require advanced filters that operate in the ultraviolet or infrared regions. Vapour deposition is the dominant coating technology used to produce these filters, but sol-gel processes have also gained a footing. These methods have been used to create organic/inorganic hybrids that can theoretically withstand larger strains than a purely inorganic metal oxide, but demonstrations of thin film filters with strain properties similar to pure polymers have been sorely lacking. A homogeneous composite featuring inorganic nanoparticles in a polymer matrix is capable of very high strains without failure. We demonstrate such a system here with a 38-layer nanocomposite filter that is subjected to 20% strain with simultaneous evaluation of optical performance. The filter's reflectance peak shifts toward the shorter wavelengths as film thickness decreases in response to the strain, but the peak intensity of the reflected light does not substantially change. These results suggest that the nanocomposite layers are behaving as homogeneous materials with consistent optical parameters throughout the test.
authors.affiliation: Optical Dynamics Nanotechnology, 10106 Bluegrass Parkway, Louisville, KY 40299, USA. tdruffel@opticaldynamics.com
authors.forename: Thad
authors.initials: T
authors.lastname: Druffel
authors.forename: Matthew
authors.initials: M
authors.lastname: Lattis
authors.forename: Megan
authors.initials: M
authors.lastname: Spencer
authors.forename: Omar
authors.initials: O
authors.lastname: Buazza