Super-Resolution Displacement Spectroscopic Sensing over a Surface "Rainbow"

Area of Science:

• Plasmonics
• Metasurfaces
• Nanophotonics
• Spectroscopy
• Biosensing

Background:

• Subwavelength light manipulation is crucial for advanced spectroscopy, sensing, and medical imaging.
• Miniaturized spectrometers are needed for on-chip spectral analysis.
• Accurate spatial-shift detection is a key challenge in imaging-based spectroscopic sensing.

Purpose of the Study:

• To develop a unique "rainbow" trapping metasurface for on-chip spectrometers and sensors.
• To demonstrate high-precision spatial-shift detection for spectroscopic analysis.
• To achieve sensitive and specific biosensing for clinical applications.

Main Methods:

• Fabrication of a plasmonic rainbow trapping metasurface.
• Integration with a low-magnification (4×) optical microscope system.
• Application of super-resolution image processing techniques.
• Demonstration of exosome detection and EGFR expression analysis.

Main Results:

• Achieved spatial-shift resolution of 35 nm on a 0.002 mm² metasurface.
• Demonstrated a spectral resolution of 0.032 nm wavelength shift.
• Attained a biosensing resolution of 1.92 × 10⁹ exosomes per milliliter.
• Successfully distinguished between patient and healthy control samples based on EGFR expression.

Conclusions:

• The developed metasurface provides a new platform for miniaturized on-chip spectroscopic analysis.
• The system enables accurate spatial manipulation of plasmonic resonances for sensing.
• This technology offers a promising approach for personalized, accurate bio/chemical sensing applications.