Synergizing fluorescence enhancement and heavy metal sensing through EIT modulation.

Area of Science:

• Plasmonics
• Nanophotonics
• Sensing

Background:

• Electromagnetically induced transparency (EIT) is a quantum interference effect with applications in optics and sensing.
• Surface plasmon polaritons (SPPs) offer unique light confinement properties at the nanoscale.

Purpose of the Study:

• To demonstrate a tunable EIT response and fluorescence enhancement in a novel nanostructure.
• To achieve sensitive detection of heavy-metal ions using the enhanced fluorescence.

Main Methods:

• Fabrication of a stacked ITO/Ag nanohole/poly(vinylpyrrolidone) (PVP) architecture using nanosphere lithography (NSL).
• Investigation of EIT through coupling between Fabry-Pérot (FP) resonances and Bloch surface plasmon polariton (SPP) modes.
• Analysis of mode field distributions and coupled-mode theory to elucidate the coupling mechanism.

Main Results:

• Achieved readily tunable EIT response and significant fluorescence enhancement.
• Demonstrated highly sensitive detection of mercury ions (Hg2+) within the EIT transparency window.
• Tuned EIT response by varying sphere diameter and etching duration in NSL.

Conclusions:

• The proposed ITO/Ag nanohole/PVP architecture enables tunable EIT and fluorescence enhancement.
• The platform facilitates sensitive heavy-metal ion detection, particularly for Hg2+.
• The cost-effective and scalable NSL fabrication method is suitable for practical EIT-based devices and sensing platforms.