▎ 摘　　要

NOVELTY - The device has a planar photonic crystal including a resonant cavity characterized by mode volume and a quality factor. The planar photonic crystal receives an input light into modes and an evanescent field. A graphene layer is positioned in proximity to the planar photonic crystal to overlap with the evanescent field of the resonant cavity, where the mode of the resonant cavity is coupled into the graphene layer by evanescent coupling. The planar photonic crystal comprises a crystal. Mode volume comprises volume on the order of cubic wavelength. USE - Coupling device e.g. waveguide and objective lens (all claimed), for coupling input light from a mode-locked laser light source into graphene utilized in optoelectronic devices for four-wave mixing. Uses include but are not limited to photodetectors, tunable broadband modulators, saturable absorbers and non-linear media. ADVANTAGE - The device provides the light source to be adapted to vary intensity of light input into the cavity, thus saturating the graphene layer and increasing quality factor for the resonant cavity to create bistability. The device can reduce power consumption of optical memories and switches by reducing the saturation threshold in the planar photonic crystal cavity. The graphene based photodetector is placed on a planar photonic crystal cavity, thus owing to the enhanced interaction and enhanced optical absorption of photons in the graphene-cavity system and enhancing efficiency of the graphene photodetector. DETAILED DESCRIPTION - The crystal is made of silicon, germanium, gallium arsenide, gallium phosphide, inditim phosphide, or polymers. An INDEPENDENT CLAIM is also included for a method for coupling input light into planar photonic crystal. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an image of planar photonic crystal cavities integrated with graphene. Optical microscope image (110) Inset image (120) Image (130) Planar photonic crystal cavity (135)