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arXiv · 1710.06998

Observation of Terahertz Radiation via the Two-Color Laser Scheme with Uncommon Frequency Ratios

L. -L. Zhang·W. -M. Wang·D. Wu·R. Zhang·S. -J. Zhang·C. -L. Zhang·Y. Zhang·Z. -M. Sheng·X. -C. Zhang
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Abstract

In the widely-studied two-color laser scheme for terahertz (THz) radiation from a gas, the frequency ratio of the two lasers is usually fixed at $ω_2/ω_1=$1:2. We investigate THz generation with uncommon frequency ratios. Our experiments show, for the first time, efficient THz generation with new ratios of $ω_2/ω_1=$1:4 and 2:3. We observe that the THz polarization can be adjusted by rotating the longer-wavelength laser polarization and the polarization adjustment becomes inefficient by rotating the other laser polarization; the THz energy shows similar scaling laws with different frequency ratios. These observations are inconsistent with multi-wave mixing theory, but support the gas-ionization model. This study pushes the development of the two-color scheme and provides a new dimension to explore the long-standing problem of the THz generation mechanism.

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L. -L. Zhang, W. -M. Wang, D. Wu, R. Zhang, S. -J. Zhang, C. -L. Zhang, Y. Zhang, Z. -M. Sheng, X. -C. Zhang. 2017-10-19. Observation of Terahertz Radiation via the Two-Color Laser Scheme with Uncommon Frequency Ratios. https://doi.org/10.1103/physrevlett.119.235001

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