Tailoring the spectral response of liquid waveguide diagnostic platforms

Area of Science:

• Biophotonics
• Optical Engineering
• Spectroscopy

Background:

• Liquid-filled waveguides are crucial for on-chip biophotonics diagnostics, particularly in fluorescence and Raman spectroscopy.
• Background signals from excitation sources and waveguide cladding photoluminescence complicate the detection of weak analyte signals.

Purpose of the Study:

• To review solid and liquid core filtering structures based on anti-resonant reflection for integrated waveguides.
• To identify key criteria for optimizing biosensor performance, including cladding materials and microfabrication processes.
• To present new findings on minimizing spurious fluorescence and tuning filter discrimination.

Main Methods:

• Review of anti-resonant reflection filtering structures integrated with waveguides.
• Analysis of cladding layer materials for minimizing photoluminescence.
• Investigation of microfabrication processes for variable spectral response.
• Experimental optimization of thermal growth conditions and liquid-core waveguide length.

Main Results:

• Anti-resonant filtering structures can effectively attenuate undesirable optical bands in waveguides.
• Optimized cladding materials and layer thicknesses are critical for spectral response.
• Minimized spurious fluorescence through optimized thermal growth conditions.
• Tunable filter discrimination achieved by adjusting liquid-core waveguide length.

Conclusions:

• Anti-resonant filtering structures offer a viable solution for enhancing signal discrimination in biophotonic platforms.
• Careful material selection and microfabrication are essential for high-performance biosensors.
• Further optimization of waveguide design and fabrication can lead to improved diagnostic sensitivity.