Observing topological phases and transitions with high harmonic generation

Speaker:  Alexis Salazar, LANL

Program Description:
Topological materials are of interest to both fundamental sciences and advanced technologies because topological states are robust with respect to perturbations and dissipation. Topological materials are characterized by topological invariants, which are hard to measure in experiments. In this talk, I will present theoretical results suggesting that high-harmonic generation (HHG) can be used to detect topological phase transitions in the paradigmatic Haldane model. We find that crossing a topological phase boundary in a medium with broken inversion and time-reversal symmetries changes the intensities of even- and odd-order harmonics polarized in directions parallel and orthogonal to the laser field. Our findings show that HHG can provide answers to fundamental questions about ultrafast electron-hole pair dynamics in topological materials.