12. W. J. Ding et al., “High-power Broadband terahertz Radiation Generation”, International Conference on Materials for Advanced Technologies (ICMAT), 23 Jun 2019.
Abstract:
Terahertz (THz) radiation has a wide range applications ranging from national security, biomedical imaging, and non-destructive inspection to remote sensing. However, it’s always challenge to generate THz radiation especially with high-power. Plasma based THz radiation, generated by hot electrons interacting with plasmas, has attracted a great deal of interest due to its potential to reach extreme high rediation radiation strength and high compactness. We explore high-power broadband THz sources based on the interaction of a femtosecond laser with various copper targets. We theoretically analyze how the THz radiations are generated by the hot electrons and plasma interaction, and then aims to achieve high peak power THz sources with optimal conditions. To do so, a homemade kinetic simulation tool, particle-in-cell (PIC) codes which are multi-dimensional, massive parallel programmed, object- oriented codes, has been developed. The fundamental coherent transition radiation mechanism is studied by a single hot electron beam crossing a vacuum-plasma interface. Various parameters, include laser intensity, incident angle, scale length of preplasma and target thickness and roughness are optimized to achieve the highest radiation power. Simulation results show that targets with a rough surface such as nanorods can significantly improve the output of the THz radiation. Experiment verification proves that 13.8 times (28 times) enhancement in the THz radiation in less than (larger than) 20 THz spectral range can be achieved with the 5 um (60um) length of copper nanorod targets , as compared to that with a polished plane copper target.
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Funding Info:
A*STAR SERC Young Individual Research Grants (YIRG No. A1784c0020)