Characterization of plasmonic effects in thin films and metamaterials using spectroscopic ellipsometry\ud

In this article, spectroscopic ellipsometry studies of plasmon resonances at metal–dielectric interfaces of thin films are reviewed. We show how ellipsometry provides valuable non-invasive amplitude and phase information from which one can determine the effective dielectric functions, and how these relate to the material nanostructure and define exactly the plasmonic characteristics of the system. There are three related plasmons that are observable using spectroscopic ellipsometry; volume plasmon resonances, surface plasmon polaritons and particle plasmon resonances. We demonstrate that the established method of exploiting surface plasmon polaritons for chemical and biological sensing may be enhanced using the ellipsometric phase information and provide a comprehensive theoretical basis for the technique. We show how the particle and volume plasmon resonances in the ellipsometric spectra of nanoparticle films are directly related to size, surface coverage and constituent dielectric functions of the nanoparticles. The regularly observed splitting of the particle plasmon resonance is theoretically described using modified effective medium theories within the framework of ellipsometry. We demonstrate the wealth of information available from real-time in situ spectroscopic ellipsometry measurements of metal film deposition, including the evolution of the plasmon resonances and percolation events. Finally, we discuss how generalized and Mueller matrix ellipsometry hold great potential for characterizing plasmonic metamaterials and sub-wavelength hole arrays

Polarization dependent and ellipsometric infrared microscopy for analysis of anisotropic thin films

Dielectric functions and anisotropic thin film properties such as electronic conductivity or molecular orientations are of high technological importance for engineering efficient optical, electronic and sensing devices. This work demonstrates for the first time how full scale polarization dependent Fourier transform infrared FTIR microscopy may be used for quantitative determination of polarized reflection coefficients of thin film samples with thicknesses down to a few nm. Out of plane and in plane optical properties of thin silicon oxide, indium tin oxide ITO and polyimide films are measured and characterized quantitatively with respect to anisotropy and thickness. Sample homogeneity is accessed using FTIR microscopic mapping. By performing measurements at multiple polarizer azimuths, we demonstrate the technique of ellipsometric microscopy. Exemplarily, ellipsometric measurements of a polyimide film are presented and discussed. We describe how introducing a retarder into the optical path would enable sensitive phase measurements via generalized infrared ellipsometric microscop

Microfocus infrared ellipsometry characterization of air exposed graphene flakes

Graphene and ultrathin graphite flakes prepared by exfoliation were characterized by microfocus synchrotron infrared mapping ellipsometry. The dielectric function of graphene in a dry-air atmosphere is determined and compared to that of ultrathin graphite, bulk graphite, and gold. The imaginary part of graphene is revealed to be about an order of magnitude higher than that of graphite and comparable to that of gold. Comparing the conductivity to an optical model considering intraband transitions, we discuss the critical effects of environmental exposure, relevant for real-world applications

Infrared ellipsometry for improved laterally resolved analysis of thin films

In the present article we discuss developments towards increasingthe spatial resolution of infraredellipsometry and ellipsometric microscopy for the study of thinfilms.Relevant aspectsinthe interpretation ofobserved peaks in the infrared ellipsometric spectra are discussed. In particular anisotropic effects in dependence of molecular orientations in organic films and the excitation of a macroscopic wave, the Berreman mode, in thin silicon oxide films are addressed. For correct interpretation of measured data optical simulations are essential to avoid incorrect conclusions on band frequency and assignment

A Surface Scientist's view on Spectroscopic Ellipsometry

none1noneMaurizio CanepaCanepa, Maurizi