An Ellipsometric Technique with an ATR Module and a Monochromatic Source of Radiation for Measurement of Optical Constants of Liquids in the Terahertz Range
- 84 Downloads
Measuring the optical constants of liquids, especially water-containing solutions, is very difficult in the terahertz range. The well-known methods of measurement of the refractive index and absorption coefficient in this range include time-domain spectroscopy and Fourier-transform spectrometry. We have developed a highly sensitive ellipsometry method for measuring the optical constants of liquids using the tunable monochromatic radiation from the Novosibirsk free-electron laser. The ellipsometer is supplemented with an internal reflection module for the measurement of highly absorbing samples. The angle of incidence on the sample in the silicon prism of the module has been optimized for maximum sensitivity to parameters to measure. Measurements of the optical constants of various liquids have been performed, and a sensitivity of 0.01 has been demonstrated.
KeywordsInternal reflection ellipsometry Terahertz range Aqueous solution Free electron laser
Operation of the user station “TeraRad,” belonging to the Novosibirsk State University, was supported by the Ministry of Education and Science of the Russian Federation. The experiments with the attenuated total reflection system was supported by the Russian Science Foundation (project N 14-50-00080). The experiments were carried out with the application of equipment belonging to the Siberian Center of Synchrotron and Terahertz Radiation (project RFMEFI62117X0012). The authors are grateful to the NovoFEL team for the invaluable support of the experiments.
- 7.Ya, Hiroyuki, M. Nagai, and K. Tanaka. "Origin of the fast relaxation component of water and heavy water revealed by terahertz time-domain attenuated total reflection spectroscopy." Chemical Physics Letters 464.4-6 166–170, 2008.Google Scholar
- 8.H. Fujiwara Spectroscopic ellipsometry: principles and applications. – John Wiley & Sons, 2007.Google Scholar
- 9.A. Dobroiu, C. Otani. "Measurement of the complex refractive index of liquids in the terahertz range using ellipsometry." Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2010 35th International Conference on. IEEE, 2010.Google Scholar
- 11.“Ellipsometry of Functional Organic Surfaces and Films,” Ellipsometry of Functional Organic Surfaces and Films, vol. 52, pp. 1–363, 2014.Google Scholar
- 14.A.Soltani, D. Jahn, L. Duschek, E. Castro-Camus, M.Koch, and W. Withayachumnankul, “Attenuated Total Reflection Terahertz Time-Domain Spectroscopy: Uncertainty Analysis and Reduction Scheme IEEE Trans.Terahertz Sci. Technol.,vol.6, no.1, pp.32–39, 2016Google Scholar
- 15.A. Soltani, L. Duschek, S.F. Busch, T. Probst, E. Castro-Camus, and M.Koch “A novel accurate methodfor attenuated total reflection spectroscopy”, in 2014 39th International Conference on Infrared Millimeter, and Terahertz waves (IRMMW-THz), 2014, pp. 1–2.Google Scholar
- 17.O. A. Shevchenko, V. S. Arbuzov, N. A. Vinokurov, P. D. Vobly, V. N. Volkov, Y. V. Getmanov, I. V. Davidyuk, O. I. Deychuly, E. N. Dementyev, B. A. Dovzhenko, B. A. Knyazev, E. I. Kolobanov, A. A. Kondakov, V. R. Kozak, E. V. Kozyrev, V. V. Kubarev, G. N. Kulipanov, E. A. Kuper, I. V. Kuptsov, G. Y. Kurkin, S. A. Krutikhin, L. E. Medvedev, S. V. Motygin, V. K. Ovchar, V. N. Osipov, V. M. Petrov, A. M. Pilan, V. M. Popik, V. V. Repkov, T. V. Salikova, I. K. Sedlyarov, S. S. Serednyakov, A. N. Skrinsky, S. V. Tararyshkin, A. G. Tribendis, V. G. Cheskidov, K. N. Chernov, and M. A. Shcheglov, “Novosibirsk free electron laser: recent achievements and future prospects,” Radiophysics and Quantum Electronics, vol. 59, no. 8–9, pp. 605–612, 2017.CrossRefGoogle Scholar
- 19.Palik, Edward D., ed. Handbook of optical constants of solids. Vol. 3. Academic press, 1998.Google Scholar
- 20.R. M. A. Azzam, N. M. Bashara Ellipsometry and polarized light. – North-Holland. sole distributors for the USA and Canada, Elsevier Science Publishing Co., Inc., 1987.Google Scholar
- 21.in catalogues of TYDEX, J. S. Co, http://www.tydexoptics.com/pdf/IR_Polarizers.pdf. Accessed 6 Nov 2018