Regularized Huygens' plasmonic wave field synthesis using a metal-clad plasmonic waveguide array.

Abstract

Huygens' principle states that point sources are the basis of optical wave field generation, and an array of point sources with complex amplitudes that are separated by subwavelength distances can generate a desired optical field distribution. In field synthesis based on the Huygens' principle, the construction of ideal point sources has been overlooked when compared to other elements in optical field synthesis engineering, such as complex modulation. However, the construction of ideal point sources should be considered an important goal because the use of non-ideal point sources generates considerable optical noise in the background of the synthesized field distribution. In this Letter, we investigate Huygens' plasmonic wave field synthesis and its regularization by analyzing the noise features that arise during wave field synthesis based on non-ideal point sources and proposing a novel structure for regularized point source construction. It is shown that the quality of plasmonic wave field synthesis based on the Huygens' principle is greatly improved with the proposed design of a structure that generates a unit point source. Practical field synthesis examples involving plasmonic focusing and Airy beams are presented in support of the proposed design.