Second harmonic generation (SHG) is a nonlinear optical response wherein incident light produces a current response at twice the frequency of the light. SHG provides an important experimental probe of quantum materials and is often exploited in optical devices. Inversion symmetry forces the SHG response to vanish, severely restricting the material platforms in which it can be observed. In this talk I will present a recent proposal for inducing SHG in inversion-symmetric topological semimetals (SMs) via the application of electrical current. I will begin with a brief overview of nonlinear optical responses, then discuss calculations of the current-induced second harmonic generation (CISHG) for toy models and realistic tight-binding models of Dirac and Weyl SMs. The results indicate that CISHG in topological SMs provides a tunable response that covers a range reaching from zero all the way to multiple orders of magnitude larger than the SHG response of inversion-breaking topological semimetals, possibly providing a method of creating switchable nonlinear optical devices.
Note: this event will be hybrid. The live talk occuring in Loomis 276 will be simultaneously broadcast via Zoom. The Zoom link will be sent to the Graduate Student and PDRA mailing lists. If you are not on one of those lists and are interested in attending, please email Cat Kengle at ckengle2@illinois.edu for the link.
