Non-perfectly-matched Bragg Diffraction and the Realization of Airy Plasmon

Abstract

In recent years, non-diffraction beam became a hot research area, especially Airy beam. Except for non-diffraction, Airy beam has some other unique amazing properties, such as self-accelerating, ballistic dynamics, self-healing, and so on. These unique properties will have a serial of possible applications, such as particle clearing, curved plasma channel, and so on. Intensive studies have been carried out on its novel properties and the potential applications, while the research enthusiasm to Airy beam still keeps growing. Since SPP is a probable candidate for the integration optics, it is of great importance to realize SPP Airy beam for manipulating the trajectory of SPP. The Bragg’s principle shows the importance in in-plane manipulation of the propagation of SPP. However, there is a great restriction with the principle which will limit the manipulations on plane wave, so that the functions realized with this principle are quite limited. In addition, the principle will limit the function to very narrow bandwidth as well. It will limit the applications in the all-optical integration with SPP. An alternative method must be proposed for the SPP manipulation. There is a principle called reciprocal lattice rod theory, which is well established in diffraction kinetics. Based on the principle, a constructive diffraction will happen even when the Bragg’s condition is not perfectly matched. This principle can be used in SPP as well. It can help to realize a nonlinear phase modulation, so that greatly improve the abilities of in-plane SPP manipulation. In this chapter, we will first discuss a diffraction phenomenon called non-perfectly-matched (NPM) diffraction, which is based on the reciprocal lattice rod theory. By taking advantage of this NPM diffraction, the phase and amplitude of the SPPs can be manipulated. We then propose an in-plane nonlinear phase modulation method with this principle and successfully realize a plasmonic Airy beam, which reveals all the major properties of Airy beams.