Emilien Prost est candidat au poste CDD IR dans l’équipe Femtomag suite au départ de Y.Brelet.

Numerous applications have emerged thanks to the development of terahertz (THz) sources and detection making such pulses an interesting tool for ultrafast science [1]. We introduce a new THz platform relying on THz generation by air-plasma induced by a two-color short laser pulse and on Air Biased Coherent Detection [2]. Using this technique, we measure the THz electric field in the time-domain and can retrieve the spectrum by taking its Fourier transform. Using air as the generation and detection medium allows for the production of high electric field strength in the MV/cm range and smooth broadband spectra, making those pulses interesting to explore ultrafast phenomena. Numerous materials exhibit ro-vibrational bands and phonons in the THz range. We used this THz platform to perform THz time-domain spectroscopy (THz-TDS) [3] of condensed phase materials. The propagation through a sample modifies the temporal profile of the THz pulse. It is thus possible to retrieve the spectral feature of a sample by comparing the Fourier transform of the temporal trace with and without sample.