Abstract-Toward Standoff Sensing of CBRN with THz Waves

• Kang Liu, 
• Xi-Cheng Zhang
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https://link.springer.com/chapter/10.1007/978-94-024-1093-8_1

With the soaring demands for remote spectroscopy in homeland security and environmental monitoring, terahertz (THz) wave sensing has drawn a significant amount of attention because of its capability to acquire chemical spectral signatures non-invasively. THz-Radiation-Enhanced-Emission-of-Fluorescence (THz-REEF) makes broadband stand-off remote spectroscopy possible, due to its omni-directional emission pattern of the fluorescence and minimal ambient water vapor absorption of THz wave near the target. Two years ago, we have demonstrated coherent THz wave detection at a distance of 30 m. The development of intense broadband table-top THz source is imperative to all the extreme THz science research, including THz remote sensing. Recently, we have also demonstrated an enhanced THz radiation using dual-color ring-Airy beam induced air-plasma compared to a Gaussian beam induced plasma. It is believed that the great tunability of ring-Airy beam, its wavepacket stability at nonlinear focus regime, and the strong resilience to turbulent medium of the Airy beam family, make the plasma induced by this novel wave a promising broadband THz source for THz remote sensing and spectroscopy.