Fig. 1. Two different target structures used in numerical simulation. (a) PNT; (b) CNT

Fig. 2. Two-dimensional spatial distributions of THz wave electric field at different moments. (a)(b) t＝35T_0;(c)(d) t＝55T₀

Fig. 3. THz wave electric field passing through point (34λ₀, 17λ₀) for two target structures. (a) Time-domain waveforms; (b) frequency-domain spectra

Fig. 4. Two-dimensional distributions of electron number density for different target structures at different moments. (a)(b) t＝35T_0;(c)(d) t＝55T₀

Fig. 5. Energy spectral distributions of hot electrons behind target at different moments. (a) t＝35T_0;(b) t＝55T₀

Fig. 6. Motion state of laser in front of target. (a)(b) Two-dimensional spatial distributions of reflected laser in front of target; (c) one-dimensional distribution of reflected laser