Characterization of the Observed Electric Field and Molecular Relaxation Times for Millimeter-Wave Chirped Pulse Instrumentation

Guillaume Dhont (1) , Cédric Bray (1) , Gaël Mouret (1) , A. Cuisset (1) , Francis Hindle (1) , Kevin Hickson (2) , Robin Bocquet (1) , Daniele Fontanari (1)

1 LPCA - Laboratoire de Physico-Chimie de l'Atmosphère
2 ISM - Institut des Sciences Moléculaires

In a chirped pulse experiment, the strength of the signal level is proportional to the amplitude of the electric field, which is weaker in the millimeter or submillimeter region than in the microwave region. Experiments in the millimeter region thus require an optimization of the coupling between the source and the molecular system and a method to estimate the amplitude of the electric field as seen by the molecular system. We have developed an analytical model capable of reproducing the coherent transient signals obtained with a millimeter wave chirped pulse setup operated in a monochromatic pulse mode. The fit of the model against the experimental data allowed access to the amplitude of the electric field and, as a byproduct, to the molecular relaxation times T 1 and T 2 .

Mots clés: chirped pulse; coherent transients; polarization; relaxation time; Rabi frequency; Bloch equations

Domaines: Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]

Guillaume Dhont, Cédric Bray, Gaël Mouret, A. Cuisset, Francis Hindle, et al.. Characterization of the Observed Electric Field and Molecular Relaxation Times for Millimeter-Wave Chirped Pulse Instrumentation. Journal of Infrared, Millimeter and Terahertz Waves, 2020, 41 (8), pp.1009-1021. ⟨10.1007/s10762-020-00716-z⟩. ⟨hal-02932920⟩