Experimental analysis of surface plasmon behavior in metallic circular slits

Using a focused ion beam, the authors fabricated metallic circular slits onto a glass substrate coated with silver film. The influence of the number of slits and the focusing light phenomena was investigated by capturing the light transmitted through the circular slits. They demonstrate experimentally that the circular grating formed by a set of periodical slits can excite both stronger surface plasmon (SP) and localized surface plasmon as the number of slits increases. They found that the SP tended to congregate at the center of the circular grating, and that the reemitted light could be used to achieve a focusing phenomenon.