PDMS 2D optical lens integrated with microfluidic channels: principle and characterization

Area of Science:

• Optics and Photonics
• Materials Science
• Biomedical Engineering

Background:

• Fluorescent spectroscopy is a powerful analytical technique, but its sensitivity can be limited in portable, on-chip detection systems.
• Integrating optical components with microfluidic devices is crucial for developing compact and efficient analytical tools.
• Polydimethylsiloxane (PDMS) is a versatile elastomer widely used in microfabrication due to its biocompatibility and optical properties.

Purpose of the Study:

• To fabricate and characterize polydimethylsiloxane (PDMS) 2D-optical lenses for improving fluorescent spectroscopy detection.
• To investigate the effect of lens curvature on light beam properties and fluorescent signal intensity.
• To enhance the sensitivity of portable, fiber-coupled, on-chip fluorescent spectroscopy systems.

Main Methods:

• Fabrication of PDMS layers with varying interfacial structures (lens curvature).
• Characterization of fabricated PDMS lenses using Scanning Electron Microscopy (SEM).
• Evaluation of optical performance by measuring fluorescent response intensity with varying lens designs and a constant dye concentration.

Main Results:

• PDMS lens curvature significantly modifies the beam properties of light exiting optical fibers.
• The use of PDMS lenses increases fluorescent response intensity compared to flat interfaces.
• A three-fold increase in the sensitivity of the on-chip detection method for fluorescent spectroscopy was achieved.

Conclusions:

• PDMS 2D-optical lenses are effective in enhancing the performance of fiber-coupled fluorescent spectroscopy.
• Optimizing lens curvature is key to improving light excitation and collection efficiency.
• This lens technology offers a promising pathway for developing more sensitive portable analytical devices.