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Spectroscopie et imagerie térahertz des systèmes d'intérêt biologique.

Abstract : This work deals with a number of examples of using terahertz radiation in order to study biological systems. We have built and characterized two similar experimental setups, each for a particular application. These setups generate and detect terahertz waves using photoconductive switches driven by a femtosecond infrared laser. The first terahertz setup, dedicated to time-domain spectroscopy, allows us to characterize different systems, more or less homogeneous, from the spectroscopic point of view, that is to determine a complex permittivity of materials and its spectral dependence. Using our terahertz spectrometer, we have studied novel polymer materials transparent both in the terahertz region and at optical wavelengths and ionic water solutions. The second setup is dedicated to the development of novel methods of terahertz imaging in the near field using an aperture. Indeed, the contrast obtained from the difference of absorption by ionic solutions provides a non-invasive way to study biological cells. Demonstrations using drosophila embryos and frog sciatic nerves were done. The two activities are linked by our work on surface plasmon-polaritons, electromagnetic waves sustained on metal surfaces that under some conditions can induce an “extraordinary” transmission through subwavelength apertures. Spectroscopic studies allowed us to understand some fundamental properties of these surface modes in order to use them in novel types of near- field probes. Key words Terahertz radiation, time-domain spectroscopy, water solutions spectroscopy, near-field imaging, surface plasmons-polaritons
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https://pastel.archives-ouvertes.fr/pastel-00005584
Contributor : Ecole Polytechnique <>
Submitted on : Wednesday, July 21, 2010 - 10:23:48 AM
Last modification on : Wednesday, January 23, 2019 - 10:28:59 AM
Long-term archiving on: : Thursday, December 1, 2016 - 10:59:06 AM

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  • HAL Id : pastel-00005584, version 1

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Alexander Podzorov. Spectroscopie et imagerie térahertz des systèmes d'intérêt biologique.. Biophysique [physics.bio-ph]. 2009. Français. ⟨pastel-00005584⟩

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