Lab

Sergei Arkadevich Kozlov's Lab

About the lab

Department of photonics and optoinformatics

Featured research (2)

Despite the growing interest in nonlinear devices and components for light by light control in the terahertz range, there is a shortage of such materials and media used for these purposes. Here, we present the calculated values of low-inertia nonlinear refractive index coefficient for electro-optical crystals used in THz time-domain spectroscopy systems such as ZnSe, ZnTe, CdTe, GaP, and LiNbO 3. The medium parameters affecting the cubic nonlinearity of the vibrational nature increase in the range of 0.5-1 THz have been determined. Comparison of theoretical calculations with known experimental results confirm the theoretical model as well as our analysis of media parameter influence on the cubic nonlinearity. In terms of applications, results obtained open up new perspectives for studying various materials in the THz frequency range.
The values of the nonlinear refractive index coefficient for various materials in the terahertz frequency range exceed the ones in both visible and NIR ranges by several orders of magnitude. This allows to create nonlinear switches, modulators, systems requiring lower control energies in the terahertz frequency range. We report the direct measurement of the nonlinear refractive index coefficient of liquid water by using the Z-scan method with broadband pulsed THz beam. Our experimental result shows that nonlinear refractive index coefficient in water is positive and can be as large as 7×10 ⁻¹⁰ cm ² /W in the THz frequency range, which exceeds the values for the visible and NIR ranges by 6 orders of magnitude. To estimate n2, we use the theoretical model that takes into account ionic vibrational contribution to the third-order susceptibility. We show that the origins of the nonlinearity observed are the anharmonicity of molecular vibrations. © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Lab head

Sergei Arkadevich Kozlov
Department
  • Department of Photonics and Optical Information Technology

Members (11)

Xi-Cheng Zhang
  • ITMO University
Maria O. Zhukova
  • ITMO University
Yuri A. Shpolyanskiy
  • ITMO University
Sviatoslav A. Stumpf
  • ITMO University
Arkadiy Drozdov
  • ITMO University
Maksim Melnik
  • ITMO University
Elizaveta Buyanovskaya
  • ITMO University
Jiapeng Zhao
Jiapeng Zhao
  • Not confirmed yet
Jiapeng Zhao
Jiapeng Zhao
  • Not confirmed yet
A. A. Korolev
A. A. Korolev
  • Not confirmed yet
Maksim Melnik
Maksim Melnik
  • Not confirmed yet
Semen V. Smirnov
Semen V. Smirnov
  • Not confirmed yet
Mikhail A Knyazev
Mikhail A Knyazev
  • Not confirmed yet

Alumni (1)

Anton N. Tcypkin
  • ITMO University