P21 – Numerical investigation of optical bistability in inhomogeneous PT -symmetric gratings

Customizing the nonlinear profile along the direction of propagation helps in the realization of low-power all-optical switches. The switching intensities are extremely low (<0.01) in the broken regime provided that the light launching direction is right. It is believed that the switching intensities in the broken regime are always higher than that of the unbroken regime. But, the proposed system displays the lowest switching intensities in the broken regime. The interplay between inhomogeneous nonlinearity, broken PT -symmetry and right light incidence gives rise to the switch-down mechanism at near-zero switching intensities.