Fig. 1. Experimental setup

Fig. 2. Experimental results at the same laser pulse energy. (a) THz waveforms at different electrode positions; (b) THz time-domain waveforms at zero voltage and 4000 V voltage; (c) change of terahertz intensity peaks at different voltages

Fig. 3. Normalized THz frequency domain waveforms at different electrode positions (the inset is corresponding THz center frequency at different electrodes positions)

Fig. 4. Variation of terahertz intensity peak with electrodes positions at different laser pulse energies

Fig. 5. Relationship between normalized THz peak intensity and electrodes positions at different powers. (a) Experimental result diagram; (b) simulation diagram