Ph.D. Candidate: Hanzhe Liu
Research Advisor: David A. Reis
Date: Thursday, August 22nd, 2019
Time: 9 am
Location: Varian 355
Title: Generation and control of solid-state high harmonics at nanoscale
High-harmonic generation (HHG) has been the heart of attosecond physics since the first experiental observation in noble gases. A recent new progress in this field is the demonstration of HHG in a crystalline bulk solid. Fundamentally, HHG from solids is a spectroscopy technique that allows us to study the fundamental high-field light-matter interaction processes happening at femto- and attosecond time scale in the condensed matter phase. In terms of application, observation of high-harmonics in solids such as semiconductors makes it possible to engineer and control the ultrafast strong light-matter interaction at nanoscales by patterning the solids target with subwavelength nanostructures, which could potentially lead to novel compact ultrafast photonic devices operating at extremely short wavelengths.
In this talk, I will present the following experiments that covers both the fundamental light-matter interaction mechanisms and the control of this highly nonlinear process at sub-wavelength scale: 1. Study of HHG from photo-excited ZnO to elucidate the competing mechanisms in the single-electron picture. 2. First demonstration of HHG from a 2D material and observation of new mechanisms. 3. Enhanced HHG from a dielectric metasurface. 4. Overcoming the strong absorption of above-gap high harmonics in a photonic structure.