Enhanced fluorescence microscopy with the Bull's eye-plasmonic chip

Area of Science:

• Nanophotonics
• Plasmonics
• Fluorescence Microscopy

Background:

• Conventional fluorescence microscopy faces limitations in detecting small nanoparticles and achieving high spatial resolution.
• Plasmonic structures offer potential for enhancing light-matter interactions in optical microscopy.

Purpose of the Study:

• To investigate the efficacy of a Bull's eye-plasmonic chip for enhancing fluorescence microscopy.
• To evaluate the chip's performance in visualizing single nanoparticles and improving spatial resolution.

Main Methods:

• Fabrication and application of a Bull's eye-plasmonic chip with concentric circles.
• Comparison of fluorescence enhancement with 1-D and 2-D periodic structures.
• Epifluorescence microscopy of single microspheres and nanospheres (200 nm, 40 nm, 20 nm).
• Optimization of fluorescence enhancement using a pinhole in the incident optical system.

Main Results:

• The Bull's eye-plasmonic chip demonstrated superior fluorescence intensity enhancement compared to other periodic structures.
• Enhanced fluorescence images of single microspheres (2 μm) and nanospheres (200 nm) were successfully obtained.
• Previously undetectable fluorescence from 40 nm and 20 nm nanospheres was observed with diffraction-limit spatial resolution.
• Incorporating a pinhole further improved fluorescence enhancement.

Conclusions:

• The Bull's eye-plasmonic chip is highly effective for enhancing fluorescence microscopy.
• It enables the detection and imaging of sub-diffraction limit nanoparticles.
• The chip shows significant potential for advanced fluorescence imaging applications.