development of an integrated process for terahertz time-domain reflecto-transmissometry with optoelectronic excitation

Defense of doctoral thesis by Raphaël PEDERIVA, for the  University  Grenoble Alpes, speciality  " OPTIC and RADIOFREQUENCIES "

Keywords :   
Radiofrequencies,THz,Time-domain spectroscopy,Material characterization,Dielectric permittivity

Abstract :
Characterizing the dielectric properties of materials is a fundamental area of research, driven by the growing need to design more efficient and effective devices in many technological applications. For example, in the field of radio frequencies, precise knowledge of the refractive index is crucial for the design, simulation and optimization of electronic devices such as antennas, filters and integrated circuits. This thesis therefore focuses on the development of a method for characterizing the refractive index of materials using a time-domain approach. This technique uses a femtosecond pulsed laser combined with the use of ultrafast photoswitches for signal generation and detection. This approach allows the measurement over a frequency range from 50 to 550 GHz. The material under test, as well as the THz generator and detector, are assembled in an integrated device that is specifically relevant to measure small-volume materials. In this work, a complete model of the measurement system and the procedure for extracting the refractive index of the material are presented. An experimental implementation is also proposed, including characterization of the refractive index of glycerol droplets of around one hundred nanoliters.

Jury members:

• Jean-François ROUX, Professor of  universities - Université Savoie Mont-Blanc : Supervisor
• Emilien PEYTAVIT, Research Manager - CNRS : Reviewer
• Vincent LAUR, Professor of  universities - University of Western Brittany : Reviewer
• Elodie RICHALOT, Professor of  universities - University Gustave Eiffel : Examiner
• Anne VILCOT,  Professor of  universities - Grenoble INP - UGA : Examiner
• Philippe ARTILLAN, Assistant professor - University Savoie Mont Blanc : Co-supervisor