Giant photon momentum locked THz emission in a centrosymmetric Dirac semimetal

• DOI: 10.1126/sciadv.add7856
• Publication Date: 2023-01-04T18:58:30Z
• Authors: Liang Cheng; Ying Xiong; Lixing Kang; Yu Gao; Qing Chang; Mengji Chen; Jingbo Qi; Hyunsoo Yang; Zheng Liu; Justin C.W. Song; Elbert E. M. Chia
• Keywords: Helicity

Strong second-order optical nonlinearities often require broken material centrosymmetry, thereby limiting the type and quality of materials used for nonlinear devices. Here, we report a giant highly tunable terahertz (THz) emission from thin polycrystalline films centrosymmetric Dirac semimetal PtSe2. Our PtSe2 THz is turned on at oblique incidence locked to photon momentum incident pump beam. Notably, find an emitted efficiency that giant: It two orders magnitude larger than standard THz-generating crystal ZnTe has values approaching noncentrosymmetric topological TaAs. Further, displays sign amplitude controlled by polarization helicity state even as absorption only weakly dependent independent. work demonstrates how drag can activate pronounced are available in materials.