In recent years, surface plasmons (SPs) have attracted great attention in micro-nano optoelectronic integration, optical imaging, biosensor, data storage. As a new type of photonics device, metasurfaces have shown enormous potential in manipulating the wavefront of SPs. However, most of the current meta-devices are polarization-sensitive since they rely on specific polarization of incidence to excite and manipulate SPs. A minority of design strategies can operate under arbitrary polarization states, but only have phase modulation, which greatly limits the capability in generating complex SP field distributions due to lacking of amplitude modulation.
To address this issue, the team of Prof. Lin Chen from Wuhan National Lab for Optoelectronics and co-operators provide a design that well-designed double-lined metallic nanoslits metasurfaces can overcome these limitations. The amplitude and phase of SPs can be independently controlled under arbitrary polarization states, by appropriately arranging the rotation angles and the positions of nanoslits. Practical metasurfaces for generating polarization-independent plasmonic Airy beams, near-field focusing, and intensity-preserved “lossless” plasmon beams are designed and fabricated, and their optical properties were experimentally characterized with near-field scanning optical microscope. The measurement results validate the generation of high-performance plasmon beams, regardless of the incident polarizations. These results pave a meaningful step toward the exploration of high-performance polarization-independent plasmon devices based on plasmonic metasurfaces.
On Sep. 13th, this work, titled as “Polarization-Independent Wavefront Manipulation of Surface Plasmons with Plasmonic Metasurfaces”, was published in Advanced Optical Materials.
Paper link:
https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202000868
Figure 1. Schematic diagram of the devices. (a) the metasurface units consist of double-lined nanoslits with the rotation angles on a gold film. (b) The schematic and scanning electron microscope images of metasurfaces for polarization-independent plasmonic Airy beam, near-field focusing, and intensity-preserved “lossless” beam.
Figure 2. The near-field scanning optical microscope measured electric field intensity. (a) Airy beam, (b) near-field focusing, and (c) intensity-preserved “lossless” beam.
