Dispersionless Phase Discontinuities for Controlling Light Propagation
详细信息 查看全文
- 作者：Lingling Huang ; Xianzhong Chen ; Holger M眉hlenbernd ; Guixin Li ; Benfeng Bai ; Qiaofeng Tan ; Guofan Jin ; Thomas Zentgraf ; Shuang Zhang
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：November 14, 2012
- 年：2012
- 卷：12
- 期：11
- 页码：5750-5755
- 全文大小：496K
- 年卷期：v.12,no.11(November 14, 2012)
- ISSN：1530-6992
文摘
Ultrathin metasurfaces consisting of a monolayer of subwavelength plasmonic resonators are capable of generating local abrupt phase changes and can be used for controlling the wavefront of electromagnetic waves. The phase change occurs for transmitted or reflected wave components whose polarization is orthogonal to that of a linearly polarized (LP) incident wave. As the phase shift relies on the resonant features of the plasmonic structures, it is in general wavelength-dependent. Here, we investigate the interaction of circularly polarized (CP) light at an interface composed of a dipole antenna array to create spatially varying abrupt phase discontinuities. The phase discontinuity is dispersionless, that is, it solely depends on the orientation of dipole antennas, but not their spectral response and the wavelength of incident light. By arranging the antennas in an array with a constant phase gradient along the interface, the phenomenon of broadband anomalous refraction is observed ranging from visible to near-infrared wavelengths. We further design and experimentally demonstrate an ultrathin phase gradient interface to generate a broadband optical vortex beam based on the above principle.