Polarisation des impulsions térahertz et développement de l'imagerie par réflexion interne totale pour l'étude d'objets d'intérêt biologique

Abstract : The terahertz domain is a vast yet largely unexplored part of the electromagnetic spectrum, in spite of the virtues conferred by its intermediary situation between radar waves and infrared. Recent technological breakthroughs now allow to generate very short terahertz pulses and to proceed to a time-resolved detection of the associated electric field. The joint determination of phase and amplitude empowers to build new measurement schemes and opens us new possibilities in the processing of collected data. The phase plays a major role in the study on phenomena involving the polarization of electromagnetic waves, and assumes a peculiar meaning when dealing with ultra-sort pulses. The study of these particularities has motivated the design of achromatic polarizing elements fitted for the terahertz range using specific dielectric reflection conditions. These elements allow harnessing the differential phases and amplitudes between the two components of the electric field, so as to generate any kind of coherent polarization state. Associated with terahertz pulses are with submilllimeter wavelengths, which provide a decent spatial resolution when it comes to image objects, while information in the time domain can still be exploited. We carried out some imaging procedures with a view to pick the ones who were the better adapted to biological imaging. In order to take advantage of the sensitivity of the waves to ionic content of solutions and to cope with the high absorption of water in this frequency range, we developed a new imaging technique based on total internal reflection phenomenon. This technique gains its sensitivity from the measurement of the phase, while having an excellent transverse resolution which is well suited when it comes to study thin biological objects such as neurons or cell layers.
Document type :
Theses
Complete list of metadatas

Cited literature [108 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/pastel-00652969
Contributor : Antoine Wojdyla <>
Submitted on : Friday, December 16, 2011 - 4:34:54 PM
Last modification on : Wednesday, January 23, 2019 - 10:29:00 AM
Long-term archiving on : Saturday, March 17, 2012 - 2:41:38 AM

Identifiers

  • HAL Id : pastel-00652969, version 1

Collections

Citation

Antoine Wojdyla. Polarisation des impulsions térahertz et développement de l'imagerie par réflexion interne totale pour l'étude d'objets d'intérêt biologique. Optique [physics.optics]. Ecole Polytechnique X, 2011. Français. ⟨pastel-00652969⟩

Share

Metrics

Record views

494

Files downloads

2278