Fig. 1. Sketch of terahertz generation from filament induced by two-color field

Fig. 2. Process of ionization and radiation at central space point

Fig. 3. Near-field terahertz spectra and waveforms under conditions with（blue-dashed line）and without（red-solid line）plasma modulation

Fig. 4. Far-field terahertz spectra and waveforms under conditions with（blue-dashed line）and without（red-solid line）plasma modulation