Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiations

Abstract Mixing the fundamental (ω) and the second harmonic (2ω) waves in the gas phase is a widely employed technique for emitting terahertz (THz) pulses. The THz generation driven by bi-chromatic fields can be described by the photocurrent model, where the THz generation is attributed to free elec...

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Main Authors: Jingjing Zhao, Yizhu Zhang, Yanjun Gao, Meng Li, Xiaokun Liu, Weimin Liu, Tian-Min Yan, Yuhai Jiang
Format: Article
Language:English
Published: Nature Portfolio 2024-12-01
Series:Communications Physics
Online Access:https://doi.org/10.1038/s42005-024-01893-2
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author Jingjing Zhao
Yizhu Zhang
Yanjun Gao
Meng Li
Xiaokun Liu
Weimin Liu
Tian-Min Yan
Yuhai Jiang
author_facet Jingjing Zhao
Yizhu Zhang
Yanjun Gao
Meng Li
Xiaokun Liu
Weimin Liu
Tian-Min Yan
Yuhai Jiang
author_sort Jingjing Zhao
collection DOAJ
description Abstract Mixing the fundamental (ω) and the second harmonic (2ω) waves in the gas phase is a widely employed technique for emitting terahertz (THz) pulses. The THz generation driven by bi-chromatic fields can be described by the photocurrent model, where the THz generation is attributed to free electrons ionized by the ω field, and the 2ω field provides a perturbation to break the symmetry of the asymptotic momentum of free electrons. However, we find that the THz radiation is amplified by one order of magnitude when driven by bi-focal bi-chromatic fields, which cannot be explained only using the photocurrent model. Meanwhile, present measurements demonstrate that the THz radiation mainly originates from the plasma created by the 2ω pulses instead of the ω pulses. Energy transfer from the 2ω beam to the THz beam during the THz generation has been observed, validating the major contribution of the 2ω beam. Furthermore, the THz bandwidth has been observed to extensively exceed the bandwidth of the pump pulse, not be explained by the photocurrent model as well. These counterintuitive results present a significant challenge for understanding strong-field nonlinear optics and simultaneously expanding various applications.
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issn 2399-3650
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publishDate 2024-12-01
publisher Nature Portfolio
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spelling doaj-art-8f938f8ec88f4f8b8a1ff025c800475c2025-08-20T02:32:26ZengNature PortfolioCommunications Physics2399-36502024-12-01711610.1038/s42005-024-01893-2Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiationsJingjing Zhao0Yizhu Zhang1Yanjun Gao2Meng Li3Xiaokun Liu4Weimin Liu5Tian-Min Yan6Yuhai Jiang7Shanghai Advanced Research Institute, Chinese Academy of SciencesSchool of Electrical Engineering, Tiangong UniversityShanghai Advanced Research Institute, Chinese Academy of SciencesCenter for Transformative Science and School of Physical Science and Technology, ShanghaiTech UniversityCenter for Transformative Science and School of Physical Science and Technology, ShanghaiTech UniversityCenter for Transformative Science and School of Physical Science and Technology, ShanghaiTech UniversityShanghai Advanced Research Institute, Chinese Academy of SciencesShanghai Advanced Research Institute, Chinese Academy of SciencesAbstract Mixing the fundamental (ω) and the second harmonic (2ω) waves in the gas phase is a widely employed technique for emitting terahertz (THz) pulses. The THz generation driven by bi-chromatic fields can be described by the photocurrent model, where the THz generation is attributed to free electrons ionized by the ω field, and the 2ω field provides a perturbation to break the symmetry of the asymptotic momentum of free electrons. However, we find that the THz radiation is amplified by one order of magnitude when driven by bi-focal bi-chromatic fields, which cannot be explained only using the photocurrent model. Meanwhile, present measurements demonstrate that the THz radiation mainly originates from the plasma created by the 2ω pulses instead of the ω pulses. Energy transfer from the 2ω beam to the THz beam during the THz generation has been observed, validating the major contribution of the 2ω beam. Furthermore, the THz bandwidth has been observed to extensively exceed the bandwidth of the pump pulse, not be explained by the photocurrent model as well. These counterintuitive results present a significant challenge for understanding strong-field nonlinear optics and simultaneously expanding various applications.https://doi.org/10.1038/s42005-024-01893-2
spellingShingle Jingjing Zhao
Yizhu Zhang
Yanjun Gao
Meng Li
Xiaokun Liu
Weimin Liu
Tian-Min Yan
Yuhai Jiang
Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiations
Communications Physics
title Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiations
title_full Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiations
title_fullStr Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiations
title_full_unstemmed Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiations
title_short Temporal-spatial manipulation of bi-focal bi-chromatic fields for terahertz radiations
title_sort temporal spatial manipulation of bi focal bi chromatic fields for terahertz radiations
url https://doi.org/10.1038/s42005-024-01893-2
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