Abstract

Dielectric nanostructures are ideal integrated components for parametric three-wave mixing due to the strong field concentration they enable. This has been experimentally shown for second-harmonic generation (SHG) and parametric down-conversion in nanowaveguides [1,2]. Waveguides in photonic crystals (PhC) provide more degrees of freedom to shape the dispersion of the guided modes, which was used to demonstrate enhanced SHG efficiency using slow-light modes [3]. However, the necessity of a photonic bandgap to achieve waveguiding constrains the design of photonic elements with PhC waveguides. Here we propose to use periodically structured nanobeam waveguides, schematically depicted in Fig. 1 (a), as efficient integrated structures for SHG. The potential of nanobeams for low loss confinement of light is evident from their use as basis for high-quality resonators [4]. We show that a simple periodic hole pattern in a nanobeam waveguide already provides some of the advantages of PhC waveguides, in particular slow-light enhanced nonlinear interactions, and allows for SHG between the guided modes.

© 2015 IEEE