Low-threshold optical bistabilities in ultrathin nonlinear metamaterials.

Optical bistability typically occurs only when the optical thickness in the device or the input light power is unfavorably large. Here we show that, for a class of plasmonic metamaterials consisting of ultrathin holey metallic plates filled with nonlinear materials, the optical bistability can occur with an ultralow excitation power. We present a realistic design working at 0.2 THz and perform full-wave simulations to quantitatively study its optical bistability properties. An analytical model is developed to explain the inherent physics and provides a general design guideline for future development.