Enhancement of fluorescence-based sensing using microstructured optical fibres

Area of Science:

• Photonics
• Materials Science
• Analytical Chemistry

Background:

• Microstructured optical fibres (MOFs) offer unique light-matter interactions.
• Optimizing fluorescence detection in MOFs is crucial for sensing applications.
• Current models often overlook the impact of localized intensity regions.

Purpose of the Study:

• To develop a generic model for excitation and fluorescence recapturing in filled MOFs.
• To identify fibre designs that maximize fluorescence enhancement.
• To demonstrate the practical application of enhanced fluorescence in fibre sensing.

Main Methods:

• Development of a generic theoretical model for light propagation and fluorescence in MOFs.
• Numerical simulations of fibre designs with varying structures and materials.
• Experimental validation using a filled, solid-core MOF with in-fibre excitation and fluorescence detection.

Main Results:

• Light-matter overlap alone is insufficient for optimal fibre design.
• Fibre designs with sub-wavelength features and high-index glasses create localized high-intensity regions.
• These localized regions lead to up to two orders of magnitude enhancement in fluorescence recapturing.

Conclusions:

• Localized high-intensity regions in MOFs significantly enhance fluorescence detection.
• This phenomenon can be effectively exploited for advanced in-fibre sensing.
• The developed model provides a framework for designing optimized MOFs for sensing.