High harmonic generation and application for photoemission spectroscopy in condensed matter

High harmonic generation (HHG) delivering attosecond pulse duration with photon energy in the extreme ultraviolet spectral range has been demonstrated as a robust table-top coherent light source, allowing for the observation and manipulation of ultrafast process within the shortest time window ever made by humans. The past decade has witnessed the rapid progress of HHG from a variety of solid targets and its application for photoemission spectroscopy in condensed matter. In this article, we review the HHG in solids and the understanding of the underlying physics of HHG, which allows all-optical band structure reconstruction. We also introduce combinations of HHG source and photoemission spectroscopy, such as angular-resolved photoemission spectroscopy and photoemission electron microscopy. With the capacity of exploring a wide momentum space and high temporal resolution, the extension of attosecond science to the field of condensed matter physics will lead to new insights into the fundamental ultrafast dynamics in novel quantum materials.