Search

In 1822 A. Fresnel described an experiment to separate a beam of light into its right- and left- circular polarization components using chiral interfaces. Fresnel's experiment combined three crystalline quartz prisms of alternating handedness to achieve a visible macroscopic separation between the two circular components. Such quartz polyprisms were rather popular optical components in XIXth century but today remain as very little known optical devices. This work shows the analogy between Fresnel's experiment and Stern-Gerlach experiment from quantum mechanics since both experiments produce selective deflection of particles (photons in case of Fresnel's method) according to their spin angular momentum. We have studied a historical quartz polyprism with eight chiral interfaces producing a large spatial separation of light by spin. We have also constructed a modified Fresnel biprism to produce smaller separations and we have illustrated the process of weak measurement for light. The polarimetric analysis of a Fresnel polyprism reveals that it acts as a spin angular momentum analyzer.

The transmission of light through low coverage regular and random arrays of glass supported silica micropillars of diameters 10 to 40 \micro\meter and height 10 \micro\meter is studied experimentally. Angle-resolved measurements of the transmitted intensity are performed at visible wavelengths by either a goniospectrophotometer or a multimodal imaging (Mueller) polarimetric microscope. It is demonstrated that for the regular arrays, the angle-resolved measurements are capable of resolving many of the densely packed diffraction orders that are expected for periodic structures of lattice constants 20 to 80 \micro\meter, but they also display features that are due to the scattering and guiding of light in individual micropillars or in the supporting glass slides. These latter features are also found in angle-resolved measurements on random arrays of micropillars of the same surface coverage. Finally we perform a comparison of direct measurements of haze in transmission for our patterned glass samples with what can be calculated from the angle-resolved transmitted intensity measurements. Good agreement between the two types of results are found which testifies to the accuracy of the angle-resolved measurements that we report., Comment: Latex, 11 pages, 10 figures

This article aims to provide a brief overview of both established and novel ellipsometry techniques, as well as their applications. Ellipsometry is an indirect optical technique in that information about the physical properties of a sample is obtained through modeling analysis. Standard ellipsometry is typically used to characterize optically isotropic bulk and/or layered materials. More advanced techniques like Mueller ellipsometry, also known as polarimetry in literature, are necessary for the complete and accurate characterization of anisotropic and/or depolarizing samples which occur in many instances, both in research and "real life" activities. In this article we cover three main areas of subject: basic theory of polarization, standard ellipsometry and Mueller ellipsometry. Section I is devoted to a short and pedagogical introduction of the formalisms used to describe light polarization. The following section is devoted to standard ellipsometry. The focus is on the experimental aspects, including both pros and cons of commercially available instruments. Section III is devoted to recent advances in Mueller ellipsometry. Applications examples are provided in sections II and III to illustrate how each technique works.

A detailed study of the pore-widening rate of nanoporous anodic alumina layers as a function of the anodization voltage was carried out. The study focuses on samples produced under the same electrolyte and concentration but different anodization voltages within the self-ordering regime. By means of ellipsometry-based optical characterization, it is shown that in the porewidening process, the porosity increases at a faster rate for lower anodization voltages. This opens the possibility of obtaining three-dimensional nanostructured nanoporous anodic alumina with controlled thickness and refractive index of each layer, and with a refractive index difference of up to 0.24 between layers, for samples produced with oxalic acid electrolytes.