Cherenkov terahertz radiation from Dirac semimetals surface plasmon polaritons excited by an electron beam<xref rid="cpb_29_3_034101fn1" ref-type="fn">*</xref><fn id="cpb_29_3_034101fn1"><label>*</label><p>Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0701000), the National Key Scientific Instrument and Equipment Development of China (Grant No. 2018YFF01013001), and the National Natural Science Foundation of China (Grant Nos. 61701084 and 61505022).</p></fn>

Cherenkov terahertz radiation from Dirac semimetals surface plasmon polaritons excited by an electron beam**

Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0701000), the National Key Scientific Instrument and Equipment Development of China (Grant No. 2018YFF01013001), and the National Natural Science Foundation of China (Grant Nos. 61701084 and 61505022).

Zhao Tao, Wu Zhenhua^†

(a) The dispersion curves of a suspending BDS film excited by an electron beam. The solid red line is the dispersion curve of a moving electron beam. The parameters: d = 2 μm, ε_∞ = 13, g = 4, T = 300 K, τ = 1.2 ps, v_F = 0.9 × 10⁶ m/s, and μ_c = 0.1 eV. (b) The dependence of the frequencies and field amplitudes of the excited SPPs on the beam energy. The inset is the electric field distributions of asymmetric SPP mode and symmetric SPP mode.