Highly efficient terahertz generation using 3D Dirac semimetals

• Main Authors: Wang, Lu, Lim, Jeremy, Wong, Liang Jie
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Electrical and electronic engineering; Dirac Semimetals; Nonlinear Optics
• Online Access: https://hdl.handle.net/10356/170539
• Institution: Nanyang Technological University

It is shown that three-dimensional Dirac semimetals are promising candidates for highly efficient optical-to-terahertz conversion due to their extreme optical nonlinearities. In particular, it is predicted that the conversion efficiency of (Formula presented.) exceeds typical materials like (Formula presented.) by >5000 times over nanoscale propagation distances. Studies show that even when no restrictions are placed on propagation distance, (Formula presented.) still outperforms (Formula presented.) in efficiency by >10 times. The results indicate that by tuning the Fermi energy, Pauli blocking can be leveraged to realize a step-like efficiency increase in the optical-to-terahertz conversion process. It is found that large optical-to-terahertz conversion efficiencies persists over a wide range of input frequencies, input field strengths, Fermi energies, and temperatures. These results could pave the way to the development of ultrathin-film terahertz sources for compact terahertz technologies.