Figure 1.

THz wave emission from the trigonal layered PtBi₂ (0001) single crystal

(A) The crystal structure of trigonal layered PtBi₂.

(B) Experimental setup of the THz emission spectroscopy.

(C) The far-field EO signals $\overrightarrow{S}\left(t\right)$$[=S_x\left(t\right)\hat{x}+S_y\left(t\right)\hat{y}]$ with x-polarized pump light. (For clarity, the error bars are not shown here, which is about 4×10⁻⁷).

(D) The Fourier transform spectra $\left|S_y\left(\text{Ω}\right)\right|$ and $\left|S_x\left(\text{Ω}\right)\right|$ corresponding to the time-domain THz waveforms in (C). The inset is the peak value of S(t) (at t=0 ps) as a function of the pump fluence, and the purple solid line is a linear fit. The error bars in the inset are the standard deviation of the experimental data.