[25p-D316-1~14] 3.6 Ultrashort-pulse and high-intensity lasers

▲ [25p-D316-3] High harmonic generation in a flat water-jet with double MIR pulses

〇(D)Tianqi Yang^1,2, Takayuki Kurihara¹, Tomoya Mizuno¹, Teruto Kanai¹, Yoshihisa Harada^1,2, Jiro Itatani¹ (1.ISSP, Univ. Tokyo, 2.GSFS, Univ. Tokyo)

Keywords:high harmonic generation, flat liquid-jet, mid-infrared radiation

We have observed odd-order high harmonics up to 11th driven by intense MIR laser pulses (3.2 μm, 44 μJ, 120 fs, 450 Hz) generated from a KTA-based OPA system. An off-axis parabolic mirror (f=25.4 mm) is selected to focus the MIR pulses onto a flat water-jet (1-3 μm thick). The double excitaion was realized by placing a split mirror pair attached to stages before the parabolic mirror. We observed a persisting interference-like signal up to 400 fs, exceeding the MIR pulse duration of 120 fs. This result is likely to reveal the interaction between the laser-induced oscillating inherent molecular dipole and the MIR electric field.