Multiple path length dual polarization interferometry

School of Physics and Astronomy, The University of Manchester, Manchester, UK.
Optics Express (Impact Factor: 3.49). 07/2009; 17(13):10959-69. DOI: 10.1364/OE.17.010959
Source: PubMed


An optical sensor for quantitative analysis of ultrathin films and adsorbed layers is described. Quantification of both layer thickness and refractive index (density) can be made for in situ and ex-situ coated films. With the use of two polarizations, in situ measurements are made via one path length in a young's interferometer arrangement while ex-situ measurements use multiple path lengths. The multiple path length young's interferometer arrangement is embodied in a solid state waveguide configuration called the multiple path length dual polarization interferometer (MPL-DPI). The technique is demonstrated with ultrathin layers of poly(methylmethacrylate) and human serum albumin.

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    • "The multiple path length dual polarization interferometer (MPL-DPI) is a modification of the DPI technology, with the same underlying principles, but with a new waveguide design which allows films coated outside of the instrument to be quantified. The experimental procedure and the method to calculate the refractive index and thickness of ex situ coated films using MPL-DPI was carried out according to a published protocol [28]. The instrument was set to operate at 20 • C. Details of the instrumentations can be found in our previous work [22] "
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