Design and Optimization of All-Dielectric Fluorescence Enhancing Metasurfaces: Towards Advanced Metasurface-Assisted...

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Optics

Background:

• Miniaturized biological sensors are crucial for in vivo liquid biopsies, driving interest in lab-on-fiber (LOF) technology.
• Optical fiber meta-tips (OFMT), integrating metasurfaces (MSs) on fiber ends, represent a breakthrough in LOF devices.
• Previous OFMTs demonstrated superior label-free sensing, but enhanced sensitivity requires new strategies.

Purpose of the Study:

• To propose and numerically investigate a novel class of labeled LOF optrodes based on OFMT.
• To design all-dielectric metasurfaces (MSs) for enhancing fluorescence emission from labeled target molecules.
• To provide guidelines for developing advanced LOF devices for labeled biosensing.

Main Methods:

• Development of a numerical environment to compute fluorescence enhancement factors.
• Design of silicon-based all-dielectric metasurfaces (arrays of nanoantennas, dimers, or trimers).
• Feasibility study on fabricating MSs on multimode fiber terminations using electron beam lithography and reactive ion etching.

Main Results:

• Numerical simulations show fluorescence enhancement factors up to three orders of magnitude with optimized dielectric MS designs.
• Electron beam lithography and reactive ion etching are viable fabrication methods for MSs on optical fiber tips.
• Analysis of a biosensing application scenario quantifies performance under realistic experimental conditions.

Conclusions:

• All-dielectric metasurfaces integrated on optical fiber meta-tips offer significant fluorescence enhancement for labeled biosensing.
• The proposed LOF optrodes have potential for high-performance in vivo liquid biopsies.
• This work provides essential design principles for future labeled LOF biosensor development.