Within the framework of a project funded by the ANR (ANR PRCI "CELESTA", France-Taiwan, coll . National Tsing Hua University and NTHU, 2018-2022) we are developing a THz spectroscopy bench using an optical pump - THz probe setup. This bench uses an amplified laser chain pumping an OPA and allows obtaining a femtosecond (40 fs) laser pulse train with an adjustable wavelength between 190 nm and 20 µm.
This equipment will initially be used to optically excite broadband semiconductors by pumping them close to their gap (UV) to study the dynamics of photo-generated carriers. We are mainly targeting three materials: ITO and GaN, which are used in the fabrication of photovoltaic cells, multimedia displays, or even THz devices, and TiO2, which will enable us to study the dynamics of free carrier generation under UV illumination and to understand the processes involved in water catalysis.
Development of a characterization platform
THz waves are no longer confined to laboratories alone and today address more and more fields of application. Thus, this project aims at structuring the THz offer proposed by the functional characterization platform OPE)N(RA-FMNT, by modernizing the THz equipments and their experimental environment. The platform will be "made available" to IMEP-LAHC's academic and industrial partners.
The objectives are to gain in efficiency (time saving on the realization of the so-called "classical" measurements) and to initiate/maintain academic and industrial collaborations. This platform will complete the offer proposed at the national level in addition to those already operational in Montpellier and Bordeaux.
The development of this platform is subsidised by the AURA region via the funding of the PLATERA project.
« Precise » THz characterization of materials
In addition, THz characterization activities applied to specific materials or devices, often in response to requests for collaboration, will continue to be carried out, for example within the framework of the NATO contract (coll. Ecole Polytechnique d'Alger) already underway to identify "sensitive" substances, or as part of a collaboration with CEA-LETI and ONERA for studies on diffusion that will begin in the summer of 2019, as part of a master's internship and then a thesis.