High-harmonic generation in ZnO driven by self-compressed mid-infrared pulses

摘要

Progress in attosecond science has relied on advancements in few-cycle pulse generation technology and its application to high-order harmonic generation. Traditionally, self-phase modulation in bulk solids has been used for the compression of moderate-energy pulses, additionally exhibiting favorable dispersion properties for mid-infrared (mid-IR) pulses. Here, we use the anomalous dispersion of Y3Al5O12 (YAG) to self-compress many-cycle pulses from a 50 kHz mid-IR OPA down to produce sub-three-cycle 10 mu J pulses and further use them to generate high-order harmonics in a ZnO crystal. In agreement with theoretical predictions, we observe a boost in the harmonic yield by a factor of two, and spectral broadening of above-gap harmonics, compared to longer driving pulses. The enhanced yield results from an increase in the intensity for the self-compressed pulses. (C) 2018 Optical Society of America