Solid-State High Harmonic Generation

High harmonic generation (HHG) is a non-linear process to create ultrashort pulses to observe electron dynamics on an attosecond timescale and to create high energy XUV/X-ray photons. HHG in solid crystals helps to understand fundamental electron dynamics and probe properties of materials. HHG from solid state media is studied using a spectrometer that detects photons in the 5-40 eV energy range. HHG from large band gap (>7 eV) materials like MgO is explored with a linearly polarized 1.2 μm wavelength laser. The experiment is performed in vacuum with a custom sample stand with laser intensities on the order of 1-10 Thz/cm². The sample used was a bulk sample of magnesium oxide with thickness of 500μm. The results showed a cutoff energy of 15-16 eV and there were three harmonic orders present in the data.