1. Proceedings
  2. I3M
  3. 2018
  4. EMSS
  5. 10.46354/i3m.2018.emss.039

Modeling of waveguide modes excitation in thin-film multilayer structures by TMpolarized Gaussian light beam

  • a Viktor I. Sokolov  ,
  • b Alexander S. Akhmanov  ,
  • c Ivan O. Goriachuk  
  • a, b, c Institute on Photonic Technologies, Federal Research Center “Crystallography and Photonics”, Russian Academy of Sciences,
  • a, bFederal Research Center “Scientific Research Institute for System Analysis”, Russian Academy of Sciences
Cite as
Sokolov V.I., Akhmanov A.S., Goriachuk I.O. (2018). Modeling of waveguide modes excitation in thin-film multilayer structures by TMpolarized Gaussian light beam. Proceedings of the 30th European Modeling & Simulation Symposium (EMSS 2018), pp. 284-288. DOI: https://doi.org/10.46354/i3m.2018.emss.039

Abstract

The prism coupling technique is widely used for measuring optical parameters of thin light-guiding films. In this technique the probe laser beam scans the interface between the measuring prism of high refractive index and the film from the side of the prism, which leads to the excitation of guided modes in the film at certain resonant angles θi. The values of resonant angles θi correspond to sharp dips in the angular reflection spectrum (so called m-lines) and are used to calculate the refractive index and thickness of the film. Recently we have shown that using prism coupling technique one can determine not only the refractive index and thickness, but also the extinction coefficient of the films from the angular width of m-lines. In this paper we propose the modified mathematical algorithm and reveal that by taking into consideration the angular divergence of the probe laser beam one can improve the accuracy of extinction coefficient measurement. The problem of guided modes excitation in the multilayer thin-film structures by TM-polarized Gaussian light beam in the prism coupling geometry is considered theoretically. By using spectral approach the analytical formulas for the reflected TM Gaussian beam are derived. The developed fitting algorithm is used to calculate optical parameters of the four-layer metal dielectric structure. It is shown that the algorithm is effective and permits to calculate optical parameters of multilayer structures in the high-coupling limit in the broad angular range.

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