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Letter
Circularly-polarized THz wave emission from a micro-thin water flow
Koji Hatanaka
Academia Sinica
Corresponding Author
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Intense THz wave sources are highly expected for further progresses in nonlinear THz science and practical implementation of non-ionizing radiation in sensing and communications. Solid-based sources have inherent limits of material breakdown, while intense laser irradiation of liquids is a promising emerging technique for THz wave and hard X-ray emission. Water-based THz emission shows intensity enhancements up to 103 times when laser-pulse pairs with nanosecond delay are used. Here we show circularly- polarized THz wave emission from thin water flow irradiated by two time-separated and linearly-polarized femtosecond laser pulses. THz time-domain spectroscopy reveals the circularly-polarized THz emission dominates 4.7 ns after the first pulse irradiation. THz wave detection delay in the spectroscopy and time-resolved micrography indicate that the THz wave emission originates from the rarefied volume in front of the flow. Radial relaxation of charges (currents) in the focal volume where ponderomotive charge depletion occurred is the origin for the circular polarization; tight focusing localized THz wave emission to the sub-wavelength region.
Keywords
THz wave emission, micro-thin water flow, THz science, non-ionizing radiation
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Circularly-polarized THz wave emission from a micro-thin water flow
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This is a preprint. It has not completed peer review.
Letter
Circularly-polarized THz wave emission from a micro-thin water flow
Koji Hatanaka
Academia Sinica
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 23 Sep, 2020
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Intense THz wave sources are highly expected for further progresses in nonlinear THz science and practical implementation of non-ionizing radiation in sensing and communications. Solid-based sources have inherent limits of material breakdown, while intense laser irradiation of liquids is a promising emerging technique for THz wave and hard X-ray emission. Water-based THz emission shows intensity enhancements up to 103 times when laser-pulse pairs with nanosecond delay are used. Here we show circularly- polarized THz wave emission from thin water flow irradiated by two time-separated and linearly-polarized femtosecond laser pulses. THz time-domain spectroscopy reveals the circularly-polarized THz emission dominates 4.7 ns after the first pulse irradiation. THz wave detection delay in the spectroscopy and time-resolved micrography indicate that the THz wave emission originates from the rarefied volume in front of the flow. Radial relaxation of charges (currents) in the focal volume where ponderomotive charge depletion occurred is the origin for the circular polarization; tight focusing localized THz wave emission to the sub-wavelength region.
Figure 1
Figure 2
Figure 3
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.