Nonlinear Terahertz Electromagnetic Waves in SrTiO<sub>3</sub> Crystals under Focusing
- 1 CIICAp, Autonomous University of State Morelos (UAEM), Cuernavaca, Mexico
- 2 CIICAp, Autonomous University of State Morelos (UAEM), Cuernavaca, Mexico
- 3 CIICAp, Autonomous University of State Morelos (UAEM), Cuernavaca, Mexico
- 4 CIICAp, Autonomous University of State Morelos (UAEM), Cuernavaca, Mexico
Abstract
The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO 3 at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias electric field the dominating nonlinearity is cubic. The frequency dispersion and nonlinearity correspond to existence of envelope solitons and the modulation instability (MI) of long input pulses, whereas in the transverse direction MI is absent. There exists a possibility to generate the regular sequences of short THz pulses due to MI in bounded SrTiO 3 crystals. The focusing of input long pulses reduces the threshold of MI, increases the output amplitudes of the short pulses, and provides more stable generation of the short pulses. It is investigated the frequency multiplication of THz electromagnetic radiation in bounded paraelectric SrTiO 3 when a bias electric field is applied. The dominating nonlinearity is quadratic there. The frequency dispersion and the transverse width of the input wave beams affect the generation of higher harmonics. It is possible to select the certain numbers of higher harmonics by means of the optimum length of the crystal, by the width of the beam of the input first harmonic, and by the focusing of the input first harmonic.
- Lee, Y.-S. (2009) Principles of Terahertz Science and Technology. Springer, N.Y.
- Perenzoni, M. and Paul, D.J. (2014) Physics and Applications of Terahertz Radiation. Springer, N.Y. http://dx.doi.org/10.1007/978-94-007-3837-9
- Ward, J.S., Chattopadhyay, G., Gill, J., Javadi, H., Lee, C., Lin, R., Maestrini, A., Maiwald, F., Mehdi, I., Schlecht, E. and Siegel, P. (2008) Tunable Broadband Frequency-Multiplied Terahertz Sources. Infrared, Millimeter and Terahertz Waves, 2008, IRMMW-THz 2008, 33rd International Conference, Caltech, 15-19 September 2008, 1-3. http://dx.doi.org/10.1109/icimw.2008.4665437
- Rez, I.S. and Poplavko, Yu.M. (1989) Dielectrics. Basic Properties and Applications in Electronics. Radio and Svyaz’, Moscow. (In Russian)
- Poplavko, Yu.M., Pereverzeva, L.P., Voronov, S.O. and Yakimenko, Yu.I. (2007) Physical Material Science. Vol. 2, Dielectrics. KPI Publ., Kiev. (In Ukrainian)
- Gevorgian, S. (2009) Ferroelectrics in Microwave Devices, Circuits and Systems. Springer, N.Y. http://dx.doi.org/10.1007/978-1-84882-507-9
- Vendik, O.G. (1979) Ferroelectrics in Microwave Technology. Sov. Radio, Moscow. (In Russian)
- Buzin, I.M., Ivanov, I.V., Belokopytov, G.V., Sychev, V.M. and Chuprakov, V.F. (1981) Low-Temperature Ferroelectrics: Dielectric Permittivity, Losses, and Parametric Interactions at Ultrahigh Frequencies. Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, 24, 6-28. (English Transl. Soviet Physics Journal)
- Gassanov, L.G., Koshevaya, S.V., Narytnik, T.N. and Omel’yanenko, M.Yu. (1978) Parametric and Nonlinear Interaction of Electromagnetic Waves in Paraelectrics. Izvestiya Vysshikh Uchebnykh Zavedenii, Radioelektronika, 21, 56-63. (English Transl. Radioelectronics and Communications Systems)
- Kamarás, K., Barth, K.L., Keilmann, F., Henn, R., Reedyk, M., Thomsen, C., Cardona, M., Kircher, J., Richards, P.L. and Stehle, J.L. (1995) The Low Temperature Infrared Optical Functions of SrTiO3 Determined by Reflectance Spectroscopy and Spectroscopic Ellipsometry. Journal of Applied Physics, 78, 1235-1240. http://dx.doi.org/10.1063/1.360364
- Yashchyshyn, Y., Godziszewski, K., Bajurko, P., Modelski, J., Szafran, M., Bobryk, E., Pawlikowska, E., Tarapata, G., Weremczuk, J. and Jachowicz, R. (2013) Tunable Ferroelectric Ceramic-Polymer Composites for Sub-THz Applications. 43rd European Microwave Conference, Nuremberg, 7-10 October 2013, 676-679.