| Autor: |
Hsin-Hui Huang, Takeshi Nagashima, Kota Kumagai, Yoshio Hayasaki, Saulius Juodkazis, Vladimir T. Tikhonchuk, Koji Hatanaka |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
|
| Zdroj: |
Light: Advanced Manufacturing, Vol 5, Pp 1-13 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
2689-9620 |
| DOI: |
10.37188/lam.2024.030 |
| Popis: |
Emission of THz radiation from air breakdown at focused ultra-short fs-laser pulses (800 nm/35 fs) was investigated for the 3D spatio-temporal control where two pre-pulses are used before the main-pulse. The laser pulse induced air breakdown forms a ~ 120 μm-long focal volume generate shockwaves which deliver a 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 tunnelling ionisation intensities (1–3) × 1016 W/cm2 and corresponded to sub-critical (transparent) plasma formation in air. Polarisation analysis of THz radiation revealed that orientation of the air density gradients generated by pre-pulses and their time-position locations defined the ellipticity of the generated THz electrical field. The rotational component of electric current is the origin of THz radiation. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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