Remote terahertz spectroscopy from extended two-color plasma filaments: The ALTESSE 2 project

Coherent time-domain spectroscopy (TDS) using terahertz radiation is valuable for fundamental science, security, and medical applications. This study investigates the performance of air-biased coherent detection terahertz spectroscopy (ABCD-THz) when an extended plasma filament is created in the air over long distances. We report on the latest results obtained within the follow-up of the ALTESSE project (BERG & PRIME;E L. et al., EPL, 126 (2019) 24001) whose objective is to measure a set of spectral signatures characterizing suspicious materials over meter-long distances. As one of the most critical steps towards routinely applying this technique, we verified the feasibility of a remote THz time-domain spectroscopy by loosely focusing two-color ultrashort laser pulses at more than 3 meters from the laser source. The absorption spectra of amino acids and explosives analyzed in such a filamentation geometry are compared with those obtained using a standard ABCD scheme where the plasma is generated at much shorter distances of & SIM; 30 cm. Copyright & COPY; 2023 EPLA

Automated summary

This study investigates the performance of air-biased coherent detection terahertz spectroscopy (ABCD-THz) when an extended plasma filament is created in the air over long distances, and explores the value of time-domain spectroscopy (TDS) using terahertz radiation in fundamental science, security, and medical applications.