Fig. 1. XPW conversion efficiency versus peak intensity of laser pulses. (a) τ=100 fs, β=22.5°; (b) τ=30 fs, β=22.5°

Fig. 2. XPW conversion efficiency versus angle β. (a) τ=100 fs, I=0.2×1012 W·cm-2; (b) τ=100 fs, I=0.8×1012 W·cm-2; (c) τ=30 fs, I=0.2×1012 W·cm-2; (d) τ=30 fs, I=0.8×1012 W·cm-2

Fig. 3. Pulse widths of XPW generated from input pulses with different widths. (a) τ=100 fs; (b) corresponding spectra shown in Fig.3 (a); (c) τ=30 fs; (d) corresponding spectra shown in Fig.3 (c)