Abstract

Purely nonlinear photonic crystals (NPCs) [1], fabricated by 2D periodic poling of ferroelectric materials, offer novel degrees of freedom to engineer the response of single step and cascaded frequency up-converters [2-3]. Recently, we demonstrated a novel configuration for frequency down-conversion in hexagonally poled LiTaO₃ (hexLT) [4], whereby two lattice resonances are coherently coupled to yield twin-beam optical parametric generation (OPG) with a shared signal or idler, significantly enhancing the OPG spectral and angular responses [5]. In this paper we show how the twin-beam OPG output in turn initiates multiple up-conversion processes (mediated by higher-order RLVs of the lattice) resulting in further enrichment of the spectral and angular range of cascaded up-conversions processes in the visible.

© 2013 IEEE