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A Tunable Freeform-Segmented Reflector in a Microfluidic System for Conventional and Surface-Enhanced Raman
Qing Liu1, Michael Stenbæk Schmidt2, Hugo Thienpont1
1Department of Applied Physics and Photonics, Brussels Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, B-1050 Brussels, Belgium.
Sensors (Basel, Switzerland)
|February 29, 2020
Summary
This study introduces a novel microfluidic system for Raman and Surface-Enhanced Raman Scattering (SERS) analysis, achieving confocal detection to reduce background noise. The system demonstrates a detection limit of 20 mM for chemical analysis.
Area of Science:
- Microfluidics
- Spectroscopy
- Optical Engineering
Background:
- Conventional Raman spectroscopy suffers from background noise, limiting sensitivity.
- Microfluidic systems offer miniaturization and precise sample handling for chemical analysis.
- Confocal detection enhances spectral resolution and signal-to-noise ratio.
Purpose of the Study:
- To develop a freeform-segmented reflector-based microfluidic system for enhanced Raman and SERS analysis.
- To enable confocal detection of Raman scattering within a polymer-based microfluidic chip.
- To assess the system's performance for chemical detection and discrimination.
Main Methods:
- Numerical design of a freeform-segmented reflector.
- Fabrication using ultra-precision diamond turning and laser cutting.
- Non-sequential ray tracing simulations with the Henyey-Greenstein model.
- Confocal Raman measurements of ethanol, urea, and potassium nitrate solutions.
Main Results:
- The system successfully achieved confocal detection, significantly suppressing background noise.
- Calibration experiments demonstrated a detection limit of approximately 20 mM for the microfluidic system.
- The Surface-Enhanced Raman Scattering (SERS) microfluidic chip discriminated between 100 µM urea and potassium nitrate solutions.
Conclusions:
- The freeform-segmented reflector-based microfluidic system provides an effective platform for sensitive Raman and SERS analysis.
- The integration of confocal detection within the microfluidic chip enhances analytical performance.
- The developed system shows promise for various chemical sensing applications.
