Asymmetric Localization by Second Harmonic Generation

In this talk, we introduce a nonlinear photonic system that enables asymmetric localization and unidirectionally transfers an electromagnetic wave through the second harmonic generation process. To achieve this, we propose a scattering setup consisting of a non-centrosymmetric nonlinear slab with nonlinear susceptibility (d) placed to the left of a one-dimensional periodic linear photonic crystal with an embedded defect. We engineered the linear lattice to allow the localization of frequency 2ω_* while frequency ω_* is in the gap. Thus in our proposed scattering setup, a left-incident coherent transverse electric wave with frequency ω_* exponentially decays through the lattice. In contrast, a generated second harmonic wave with frequency 2ω_* localizes at the defect layer. For a right-incident wave, our optical setup acts as a mirror and wholly reflects the incident wave. Our proposed structure will find application in designing new optical components such as optical sensors, switches, transistors, and logic elements.