Highly Efficient Terahertz Generation Using 3D Dirac Semimetals

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 predicted the efficiency of Cd 3 As 2 $\text{Cd}_{\text{3}}\text{As}_{\text{2}}$ exceeds typical materials like LiNbO $\text{LiNbO}_{\text{3}}$ by >5000 times over nanoscale propagation distances. Studies show even when no restrictions placed on distance, still outperforms in >10 times. The results indicate tuning Fermi energy, Pauli blocking can be leveraged realize a step-like increase process. found large efficiencies persists wide range input frequencies, field strengths, energies, and temperatures. These could pave way development ultrathin-film terahertz sources compact technologies.