The Research On Tunable Optical Bistability Based On Graphene

Optical bistability in nonlinear optics is a very important study,which beams through an optical system is a nonlinear change in light intensity of optical phenomena,based on input-output characteristic curve of intensity has this kind of magnetic hysteresis loop of the main character.This feature can be used to produce optical switches,optical storage,optical power limiting optical device,optical logic functions,is characterized by low power consumption,short response time,are not affected by radio frequency interference in optical information processing and communication is an important value.A new two-dimensional material Graphene is,have revealed a wealth of new physical properties and great potential,to enter into new low-dimensional physics and practical application of the fertile soil.This paper is based on superior optical control characteristics of Graphene;Graphene research controlled bistable optical phenomena,using one-dimensional Photonic crystals,modified Fabry-Perot cavity,as well as improvement of Otto structure,optical bistability.Main research contents are as follows:The photoelectric controllable characteristics of the superior graphite,in this paper,the controllable nonlinear optics study based on the new two-dimensional material graphene is carried out,the optical bistable is realized by using one-dimensional photonic crystals,Fabry-Perot cavity,and improved Otto structure,and the low threshold adjustable optical bistable is investigated.The main research contents are as follows:(1)Graphene thin film attached to a nonlinear defect layer on both sides revealed few-layer Graphene on the influence of the nonlinear effect in one-dimensional Photonic crystals.Studies have found that although the Graphene thin film thickness is small,but they can significantly change the structure of nonlinear transmission responses,including optical bistable threshold,interval width and optical bistability of nonlinear lateral displacement,in which optical bistable threshold with the graphite Fermi as well as Graphene thin film layers increases.Moreover,in addition to the parameters of the Graphene itself,the incident light angle optics optical bistable bistable threshold and interval width also influenced.(2)Study on improvement of nonlinear in Graphene films of Fabry-Perot cavity tunable Terahertz-wave optical bistability,found using Fabry-Perot cavity will significantly reduce the trigger threshold of optical bistability,Fabry-Perot cavity after joining the Graphene films can be increased regulation and hysteresis response.By the applied voltage,Graphene carrier density flexible electrical or chemical regulations are the main reason increases and adjust the hysteresis effect.Further research found that lens transmission rate,length,location of the Fabry-Perot cavity of Graphene and Graphene relaxation time can effect of optical bistability.(3)Research on a nonlinear electronic media cover Graphene film on a substrate to improve optical hysteresis response of Otto structure through strong local field of surface Plasmon enhanced found optical bistable threshold decreases significantly.When Graphene thin film layers to five layers,optical bistable threshold is reduced by about three orders of magnitude.In addition,reveals the effect of the characteristics of Graphene(such as Fermi,and relaxation time),the thickness of the air layer,incident angle and wavelength of the light on the behavior of optical bistable.