Multistable response of trapping light nonlinear structures

We present our recent results related to effects of bistability, multistability, and nonreciprocity in a finite layered photonic band-gap chiral structure with an asymmetrically introduced nonlinear defect and in a very thin planar meta-material consisted of a peculiar patterned metal layer placed on a nonlinear substrate. Remarkable feature of both kinds of these structures is a bearing of a strong localized high-intensity electromagnetic field. We argue that an application of this so-called trapped mode resonance operation is a promising technique to design all-optical control devices.