Version 1
: Received: 29 November 2023 / Approved: 29 November 2023 / Online: 29 November 2023 (10:53:19 CET)
How to cite:
Huang, H.; Nagashima, T.; Kumagai, K.; Hayasaki, Y.; Juodkazis, S.; Tikhonchuk, V.T.; Hatanaka, K. Fine 3D Control of THz Emission in Air with Dual Femtosecond Laser Pre-pulses at Tunnelling Ionisation Regime. Preprints2023, 2023111861. https://doi.org/10.20944/preprints202311.1861.v1
Huang, H.; Nagashima, T.; Kumagai, K.; Hayasaki, Y.; Juodkazis, S.; Tikhonchuk, V.T.; Hatanaka, K. Fine 3D Control of THz Emission in Air with Dual Femtosecond Laser Pre-pulses at Tunnelling Ionisation Regime. Preprints 2023, 2023111861. https://doi.org/10.20944/preprints202311.1861.v1
Huang, H.; Nagashima, T.; Kumagai, K.; Hayasaki, Y.; Juodkazis, S.; Tikhonchuk, V.T.; Hatanaka, K. Fine 3D Control of THz Emission in Air with Dual Femtosecond Laser Pre-pulses at Tunnelling Ionisation Regime. Preprints2023, 2023111861. https://doi.org/10.20944/preprints202311.1861.v1
APA Style
Huang, H., Nagashima, T., Kumagai, K., Hayasaki, Y., Juodkazis, S., Tikhonchuk, V.T., & Hatanaka, K. (2023). Fine 3D Control of THz Emission in Air with Dual Femtosecond Laser Pre-pulses at Tunnelling Ionisation Regime. Preprints. https://doi.org/10.20944/preprints202311.1861.v1
Chicago/Turabian Style
Huang, H., Vladimir T. Tikhonchuk and Koji Hatanaka. 2023 "Fine 3D Control of THz Emission in Air with Dual Femtosecond Laser Pre-pulses at Tunnelling Ionisation Regime" Preprints. https://doi.org/10.20944/preprints202311.1861.v1
Abstract
Two pre-pulses focused at different positions and at different time moments were used to enhance THz emission generated by the main pulse. The emission of THz radiation from air breakdown regions of focused ultrashort fs-laser pulses (800 nm/35 fs) at shockwave front prepared by pre-pulses was investigated, and a 3D spatio-temporal control was established for the most intense emission. The laser pulse-induced air breakdown forms a ~120 micrometers-long focal volume and generates a shockwave that delivers denser air into the focal region of the main pulse for enhanced generation of THz radiation at 0.1-2.5 THz spectral window. The intensity of pre- and main-pulses was at the tunneling ionisation intensities (1-3)x1016 W/cm2 and corresponded to sub-critical (transparent) plasma in air. Polarisation analysis revealed that the orientation of the air density gradients generated by pre-pulses and their time-space placement defined the ellipticity of the generated THz electrical field. The rotational electric current is the origin of THz radiation. The current is created by non-parallel gradients of electron density and temperature. Scaling dependencies of THz emission control are established.
Keywords
THz radiation; femtosecond laser-induced breakdown; air breakdown; spatiotemporal control; coupling of temperature; density gradients in plasma; tunnelling ionisation
Subject
Physical Sciences, Radiation and Radiography
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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