Ultrasensitive refractometric sensing via centimeter-scale metasurfaces with spatially gradient geometry generated by...

Area of Science:

• Nanophotonics
• Materials Science
• Optical Engineering

Background:

• Plasmonic metasurfaces offer advanced light manipulation, but fabrication is costly and complex.
• Gradient geometry metasurfaces can eliminate chromatic aberration and control light phase.
• Current methods limit practical applications due to fabrication and characterization challenges.

Purpose of the Study:

• To develop a novel, cost-effective nanofabrication method for centimeter-scale gradient plasmonic metasurfaces.
• To demonstrate the capability of the fabricated metasurfaces in manipulating light and sensing applications.
• To overcome the limitations of conventional lithographic techniques.

Main Methods:

• Directional stretching of a trapezoid elastic carrier patterned with regular metallic nanostructures.
• Fabrication of centimeter-scale metasurfaces with spatially gradient geometry.
• Characterization of metasurface transmittance under monochromatic and polarized light illumination.

Main Results:

• Achieved centimeter-scale metasurfaces with spatially gradient geometry.
• Demonstrated variable transmittances and grayscale pattern generation.
• Obtained ultrahigh imaging-based sensitivity (1495 pixel/RIU) and a low detection limit (0.00068 RIU).

Conclusions:

• The novel stretching method provides an efficient and affordable way to produce gradient plasmonic metasurfaces.
• The fabricated gradient metasurfaces show superior performance for sensing applications compared to regular metasurfaces.
• This strategy is promising for widespread nanophotonics applications.