High Efficiency Terahertz Emission from Weyl Semimetal EuCd₂Sb₂ Single Crystals

Xin-Yun Chang^1*, Yen-Chen Ko¹, Sheng-Kai Huang¹, Yi-Cheng Cheng¹, Ying-Kuan Ko¹, Jiun-Haw Chu³, Cheng-Chien Chen⁴, Chien-Ming Tu¹, Jiunn-Yuan Lin², Chih-Wei Luo¹

¹Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
³Department of Physics, University of Washington, Seattle,WA, USA
⁴Department of Physics, University of Alabama at Birmingham, Birmingham,AL, USA

* Presenter:Xin-Yun Chang, email:abc25956021.sc11@nycu.edu.tw

We report on the high-efficiency terahertz (THz) radiation generated by Weyl semimetal EuCd₂Sb₂ single crystals under ultrafast optical excitation. The amplitude of THz radiation from EuCd₂Sb₂ is significantly greater than that observed from standard materials such as LiNbO₃ and InAs under the same conditions. To further investigate the THz generation mechanism, we conducted sample orientation measurements and comparative analyses with various standard samples. Our findings indicate that the THz emission is predominantly influenced by multiple mechanisms, with optical rectification (OR) being the primary effect.

Keywords: Terahertz emission, Weyl semimetal, Nonlinear optics