10. W. J. Ding et al., “Coherent Transition Radiation in THz range from Laser-Plasma Interaction”, 4th Global Summit & Expo On Laser Optics and Photonics, 15 Apr 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 extremely high intensity and compactness. We explore high-power broadband THz sources based on the interaction of a femtosecond laser with solid plasma targets. We theoretically analyze how the THz radiations, which are coherent transition radiation, generated by hot electrons and plasma interaction, and then aims to achieve high peak power THz sources with optimal conditions. The fundamental coherent transition radiation mechanism is studied by 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. Experiments and simulation results show that targets with a rough surface such as nanorods can significantly improve the output of the THz radiation. 13.8 times enhancement in the THz radiation in less than 20 THz spectral range can be achieved with the 5 um length of copper nanorod targets , as compared to that with a polished plane copper target.
License type:
Funding Info:
A*STAR SERC Young Individual Research Grants (YIRG No. A1784c0020)