Tracing Air-Breakdown Plasma Characteristics from Single-Color Filament Terahertz Spectra

• Published in: Journal of infrared, millimeter and terahertz waves Vol. 41; no. 9; pp. 1105 - 1113
• Main Authors: Mokrousova, D. V., Savinov, S. A., Seleznev, L. V., Rizaev, G. E., Koribut, A. V., Mityagin, Yu. A., Ionin, A. A., Nikolaeva, I. A., Shipilo, D. E., Panov, N. A., Ushakov, A. A., Savel’ev, A. B., Kosareva, O. G., Shkurinov, A. P.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2020; Springer Nature B.V
• Subjects: Angles (geometry); Bolometers; Broadband; Classical Electrodynamics; Collision rates; Computer simulation; Divergence; Electrical Engineering; Electronics and Microelectronics; Engineering; Femtosecond pulses; Geometry; Instrumentation; Lasers; Mathematical models; Measurement techniques; Optical radiation; Physics; Plasma; Pulse propagation; Radiation; Simulation; Spectra; Spectrum analysis; Terahertz frequencies; Broadband terahertz generation; Air breakdown plasma; Collision rate; Femtosecond pulse
• ISSN: 1866-6892; 1866-6906
• DOI: 10.1007/s10762-020-00688-0

In this paper, we measure broadband terahertz spectra from a single 744-nm filament produced in tight, medium, and loose geometrical focusing conditions. Terahertz spectra are measured using interferometer coupled to a helium-cooled bolometer avoiding any cutoff frequencies. Based on THz spectrum maximum position and spectral width, we estimate electron-heavy particle (neutrals and ions) collision rate. Numerical simulations are performed using the state-of-the-art model of unidirectional femtosecond pulse propagation and convergence/divergence of optical radiation at large angles.