摘要
Near-field plates with the capabilities of modulating the near-field pattern and forcing the incident wave to a subwavelength spot have been experimentally investigated at microwave wavelengths.Their superlensing properties result from the radiationless electromagnetic interference.However, the material's loss and limitations of state-of-the-art nanofabricating technology pose great challenges to scale down the microwave near-field plates to the infrared or optical region.In this paper, a related but alternative approach based on metasurface is introduced which breaks the near-field diffraction limit at mid-infrared region(10.6 μm).The metasurface consists of periodic arrangement of chromium dipolar antennas with the same geometry but spatially varying orientations, which plays the dual roles in achieving the prescribed amplitude modulation and the abrupt π phase change between the subwavelength neighboring elements.As a result, a two dimensional subdiffraction focus as small as 0.037λ~2 at ~0.15λ above the metasurface is presented.In addition, the broadband response and ease fabrication bridge the gap between the theoretical investigation and valuable applications, such as near-field data storage, subdiffraction imaging and nanolithography.
Near-field plates with the capabilities of modulating the near-field pattern and forcing the incident wave to a subwavelength spot have been experimentally investigated at microwave wavelengths.Their superlensing properties result from the radiationless electromagnetic interference.However, the material's loss and limitations of state-of-the-art nanofabricating technology pose great challenges to scale down the microwave near-field plates to the infrared or optical region.In this paper, a related but alternative approach based on metasurface is introduced which breaks the near-field diffraction limit at mid-infrared region(10.6 μm).The metasurface consists of periodic arrangement of chromium dipolar antennas with the same geometry but spatially varying orientations, which plays the dual roles in achieving the prescribed amplitude modulation and the abrupt π phase change between the subwavelength neighboring elements.As a result, a two dimensional subdiffraction focus as small as 0.037λ~2 at ~0.15λ above the metasurface is presented.In addition, the broadband response and ease fabrication bridge the gap between the theoretical investigation and valuable applications, such as near-field data storage, subdiffraction imaging and nanolithography.
出处
《光电工程》
CAS
CSCD
北大核心
2017年第3期331-339,共9页
Opto-Electronic Engineering
基金
supported by the National Natural Science Funds (61575032)