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Self-organized nonlinear gratings for ultrafast nanophotonics

Published

Author(s)

Daniel D. Hickstein, David R. Carlson, Haridas Mundoor, Jacob B. Khurgin, Kartik A. Srinivasan, Daron A. Westly, Abijith S. Kowligy, Ivan I. Smalyukh, Scott A. Diddams, Scott B. Papp

Abstract

We present the first demonstration of automatically quasi-phase-matched second-harmonic generation using femtosecond pulses. The high-confinement geometry of silicon-nitride nanophotonic waveguides provides group-velocity matching, which enables efficient second- harmonic generation over a broad bandwidth. We confirm the presence of self-organized gratings by using nonlinear optical microscopy to record the first direct images of photo-induced nonlinear gratings. Furthermore, we demonstrate how these waveguides enable simultaneous 𝜒(2) and 𝜒(3) nonlinear processes, which we utilize to stabilize a laser frequency comb. Finally, we derive the equations that govern self-organized grating formation for femtosecond pulses and explain how nanophotonic waveguides could enable scalable, reconfigurable nonlinear optical systems.
Citation
Nature Photonics

Keywords

frequency combs, group-velocity matching, nanophotonics, second-harmonic generation, self- organized gratings, silicon nitride, ultrafast optics
Created June 3, 2019, Updated May 29, 2020