Super-oscillatory metasurface doublet for sub-diffraction focusing with a large incident angle

Area of Science:

• Optics
• Metamaterials
• Nanophotonics

Background:

• Optical super-oscillatory phenomena enable sub-diffraction focusing and super-resolution imaging.
• Existing methods are limited by sensitivity to incident angle, restricting the field of view.

Purpose of the Study:

• To propose a super-oscillatory metasurface doublet for far-field sub-diffraction focusing.
• To achieve robust sub-diffraction focusing across a wider range of incident angles.

Main Methods:

• Design and simulation of a metasurface doublet composed of high-aspect-ratio rectangular nanopillars.
• Utilizing full-wave simulation to validate the optical performance.

Main Results:

• The proposed metasurface doublet achieves far-field sub-diffraction focusing up to an incident angle of 25°.
• Sub-diffraction foci, approximately 0.75 times the diffraction limit, were observed across various incident angles.
• The metasurface demonstrated high focusing efficiency.

Conclusions:

• The super-oscillatory metasurface doublet effectively overcomes the angular sensitivity limitations of traditional super-oscillatory fields.
• This technology holds promise for advanced applications in label-free super-resolution microscopy and precise optical fabrication.