Single-mode porous silicon waveguide interferometers with unity confinement factors for ultra-sensitive surface...

Area of Science:

• Photonics and optical engineering
• Materials science
• Nanotechnology

Background:

• Guided wave-optics are promising for label-free biosensing.
• Current devices face limitations in sensitivity due to evanescent field interaction and low confinement factors.

Purpose of the Study:

• To develop a mesoporous silicon waveguide biosensor with enhanced sensitivity.
• To overcome the limitations of evanescent field interaction in current biosensing platforms.

Main Methods:

• Designed and fabricated a mesoporous silicon waveguide using an inverse fabrication technique.
• Characterized the waveguide sensors in a Fabry-Perot interferometer configuration.
• Investigated the role of dispersion in enhancing sensor sensitivity.

Main Results:

• Achieved maximal transverse confinement factors while preserving single-mode operation.
• Demonstrated ultra-high sensitivity to small molecule adlayers.
• Identified dispersion as a key factor for exceeding conventional sensitivity limits.

Conclusions:

• The novel mesoporous silicon waveguide design effectively resolves evanescent field interaction limitations.
• This approach offers a promising pathway for developing next-generation, ultra-sensitive label-free biosensors.
• Dispersion engineering presents a novel strategy for further enhancing biosensing capabilities.