All-optical diode based on plasmonic attenuation and nonlinear frequency conversion

We present design of an all-optical diode in a metal-dielectric structure where plasmonic attenuation and quasi-phase-matching (QPM) is harnessed to improve its performance greatly. Due to the anti-symmetric design of the nonlinear susceptibility, different incident direction will ignite different plasmonic nonlinear process, which either compensates plasmonic attenuation sufficiently or accelerates it seriously. As a result, unidirectional output of plasmonic signal is achieved. This designed all-optical diode shows advantages of low power consumption, short sample length, high isolation contrast, wide acceptance of structural and initial conditions, and tunable unidirectionality, and becomes of practical interest.