Elliptically Polarized THz Generation and Manipulation from Layered Two-dimensional Materials

Elliptically polarized terahertz (THz) emitter with tunable polarization state utilized in THz time-domain spectroscopy has intriguing potential for various applications, such as data processing, medical diagnosis, chiral molecular analysis, and so on. With the rapid development of material science, two-dimensional (2D) materials have been seen as the efficient and burgeoning nanoscale THz sources due to the high carrier concentration and mobility, broad spectral response, adjustable band gap, and especially the spin-related physics. Herein, we have observed the elliptically polarized THz generation from the tin sulfide (SnS) excited by linearly polarized incident light. Interestingly, the ellipticity and the orientation angle of the reconstructed THz polarization ellipses are dependent on the pump light polarization angle, realizing the arbitrary control of the polarized THz emission. Our study could lay the foundation for the 2D materials-based compact and integrated THz emitters and modulators.