2026-10-13T09:53:36Z https://www.scidb.cn/oai

10.57760/sciencedb.16830 2024-04-02T17:05:45Z

2024-04-02 Terahertz-triggered ultrafast nonlinear optical activities in two-dimensional centrosymmetric PtSe₂ doi:10.57760/sciencedb.16830 en The nonlinear mechanisms of polarization and optical fields can induce extensive responses in materials. In this study, we report on two kinds of nonlinear mechanisms in the topological semimetal PtSe₂ crystal under the excitation of intense terahertz pulses, which are manipulated by the real and imaginary parts of the nonlinear susceptibility of PtSe₂. Regarding the real part, the broken inversion symmetry of PtSe₂ is achieved through terahertz electric field polarization approach, which is characterized by second harmonic generation (SHG) measurements. The transient terahertz-laser-induced SHG signal occurs within 100 fs and recombines to the equilibrium state within 1 ps, along with a high signal-to-noise ratio (~51 dB) and a high on/off ratio (~10²). Regarding the imaginary part, a nonlinear absorption change can be generated in the media. We reveal a terahertz-induced absorption enhancement in PtSe₂ via nonlinear transmittance measurements, and the sheet conductivity can be modulated up to 42% by terahertz electric fields in our experiment. Therefore, the terahertz-induced ultrafast nonlinear photoresponse reveals the application potential of PtSe₂ in photonic and optoelectronic devices in terahertz technology. THz source; PtSe2; polarization 桑建华 陈昕 王康 郑卓锐 方依霏 王俊 吴晓君 宋立伟 田野 冷雨欣 李儒新 PUBLIC https://creativecommons.org/publicdomain/zero/1.0/ dataset Science Data Bank