Characterization of solid complex multiphase systems based on oscillatory photon correlation spectroscopy.

The particle loading and dispersion profiles are two significant properties directly affecting the engineering properties and performance characteristics of polymer nanocomposites. Current measurement techniques are often destructive, require special sample preparation, are limited to small, unrepresentative sample size, and/or cannot discriminate between the two aforementioned parameters. This Letter demonstrates the application of photon correlation spectroscopy on mechanically oscillated solids; experimental results show that this technique can discriminate between different grades of such materials.

Optical coherence refractometry.

We introduce a novel approach to refractometry using a low coherence interferometer at multiple angles of incidence. We show that for plane parallel samples it is possible to measure their phase refractive index rather than the group index that is usually measured by interferometric methods. This is a significant development because it enables bulk refractive index measurement of scattering and soft samples, not relying on surface measurements that can be prone to error.