Credit: Light: Science & Applications
Fig. 3 (a) Typical white light spectra after filamentation with (FIL+55 kV) and without (FIL) external DC electric field together with the initial laser spectrum (no FIL) for comparison. Each spectral distribution was normalized at its maximum. (b) The SNR of the SC spectral intensities when the laser was working at 1 kHz under different polarities (positive and negative) of the DC electric field. (c) The SC laser energy obtained as a function of pump laser energy under 1m focusing condition.