Asymmetric Transport Using Nonlinear Parity-Time Symmetric Structures

This thesis advocates for a physical mechanism which induces significant asymmetric wavetransport in scattering systems –ensuring or inhibiting substantial wave-transmission depending upon the direction of an incident wave. The specific components underpinning this mechanism are active nonlinear-elements with balanced amplification and attenuation. Initially, the validity of this mechanism is demonstrated in the framework of electronics. Subsequently the notion of directional nonlinear Fano-resonances, occurring in the presence of balanced amplification and attenuation, is incorporated into the previous design: thereby enhancing the observed asymmetry to the point of achieving giant asymmetric wave-transport. The observed non-reciprocity does not require the presence of magnetic elements, occurs for a broad range of input power, and is entirely independent of higher-harmonic generation. The hope is that the setup can be implemented as a diode in micron-scale photonic systems.