Directional Design of Optical Lens Based on Metallic Nano-slits by Yang-Gu Algorithm

摘要

Directional design of optical lenses based on metallic nano-slits that can focus light in different style by Yang-Gu (YG) algorithm. Both of the relative phase and amplitude of emitting light scattered by surface plasmon in a single subwavelength slit and modulated by the width of the slit or the thickness of the lens of the lens have been considered in the design processing. A form of the YG algorithm which considers both the phase and amplitude changing is derived. Two kinds of nanolenses are designed by this numerical method, one with one focal spot, and another with two focal spots in one focal plane. According to the finite-different time-domain (FDTD) method numerical calculation, it is found that the functions of the designed lenses agree well with preassigned goal. This method may be useful to design subwavelength optical devices that can be integrated into other optical and optoelectronic elements.