Application of terahertz microscopy in biophotonics and microfluidics
V.A. Zhelnov1, D.R. Il’enkova1, D.D. Rybnikov1, D.S. Ustyantseva1, V.V. Koroleva1, K.I. Zaytsev1, N.V. Chernomyrdin1; 1 – Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
Abstract
Terahertz (THz) technologies are increasingly employed in biophotonics and medical diagnostics. Nevertheless, THz optical systems still suffer from several intrinsic limitations, among which one of the most important is low spatial resolution. In this work, we present super-resolution THz microscopy techniques based on the solid immersion (SI) effect. This method enables overcoming the Abbe diffraction limit by focusing an electromagnetic beam in the near-field region behind a high-refractive-index SI lens. Continuous-wave THz SI microscopy provides spatial resolution down to 0.15λ (λ is the free-space wavelength) when using a high-resistivity silicon SI lens, and down to 0.06λ when employing a rutile SI lens. Pulsed THz SI microscope provides resolution down to 0.047λ when visualizing objects with π phase change. We applied THz SI microscope to study dielectric objects as well as various healthy and pathological biological tissues ex vivo. Moreover, we combined the THz SI microscope with a linear polarizer and analyzer and applied it to examine the optical anisotropy of different tissue types ex vivo from rats. We developed a microfluidic chip combined with reference silicon window of the microscope and applied it to study THz responses of small volumes of immersive optical clearing agents, as well as for measuring diffusion coefficients of agents into the hydrogel.
Speaker
Nikita V. Chernomyrdin
Prokhorov General Physics Institute of the Russian Academy of Sciences
Russia
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