Optical Bistability In The Quantum Dot-Metal Nanoparticle Hybrid System

In this technological age,nano-technology has been integrated in people's daily life.With the continuous development of nanofabrication techniques and people's growing needs,composite nanomaterials with multifunction come into beingwhile nanomaterials with single function will eventually be eliminated.Nanoparticles of this composite system are comprised of semiconductor quantum dots,metal nanoparticles,and magnetic materials.Composite systemsnot only have intrinsic physical characteristic of each component,but also have some derived functions due to the coupling effect of each component.The background of materials is the quantum dots-metal nanoparticles composite system in this paper.Optical bistable systems have wide application prospect in fields such as optical switch,optical information storage and so on,so extensive researches have been conducted in optical bistable devices.For the improvement of understanding in composite system,especially the inspiration of the existence of Kerr nonlinear optical effect in the composite system of quantum dots-nanoparticles,we focus on the optical bistability in quantum dots-metal nanoparticles composite system in this paper.The main research in this paper is divided in two parts:First part:We take advantage of surface excimer effect from metal nanoparticles to enhance the optical bistable.We found that the optical bistable is prone to appear when the direction of applied probe field perpendicular to the main spindle of composite system.Besides,the threshold of the optical bistable decreases as the distance between quantum dots and metal nanoparticles decreases.And we still found that the threshold and area of the optical bistable of the composite system can be regulated by changing the radius of metal nanoparticles and the frequency of applied field.Second part:The effect of the size and structure of metal nanoparticles on optical bistability is also investigated in this paper.Results show that for ellipsoidal nanoparticles,the normalized Rabi frequency,self-interaction phase and extinction coefficient will simultaneously be affected by long and short axis of the axle of metal nanoparticles.At the end of this paper,we will conduct a summary and outlook.Third part:We study the optical bistability in the quantum dots-metal nanoparticle hybrid system.And we find that there is a very large potential applications or the light switch and the information processing.