ABSTRACT:

Harnessing nonlinear light–matter interactions in on‐chip photonic systems has opened new pathways for manipulating optical fields. An interesting example is the generation of photocurrents in amorphous integrated platforms, which can drive efficient frequency‐doubling processes. In these materials, the coherent photogalvanic effect—based on the quantum interference between different multiphoton absorption channels—breaks the inversion symmetry and produces a second‐order response where none exists intrinsically. Although this mechanism has enabled applications in classical and quantum photonics, a detailed understanding of its operational limits and dynamical behavior has remained elusive. In this talk, we discuss theoretical and experimental studies of the coherent photogalvanic effect in integrated optical waveguides, demonstrate generalized sum-frequency generation and other second-order nonlinear effects, and analyze the dynamics governing frequency doubling as well as the effect of material properties for optically induced second-order nonlinearities.

BIO:

Dr. Ozan Yakar received his BSc (H. Hon.) in Electrical Engineering and Physics from Boğaziçi University, Istanbul, in 2019, and his PhD in Photonics from the École Polytechnique Fédérale de Lausanne (EPFL) in 2024. He is currently a postdoctoral researcher at the Photonics Systems Laboratory, EPFL, with research interests in integrated nonlinear photonics.