Kinoform microlenses for focusing into microfluidic channels

Area of Science:

• Optics and Photonics
• Microfluidics
• Biomedical Engineering

Background:

• Microflow cytometry requires precise optical detection within microfluidic channels.
• Conventional integrated planar lenses are often based on spherical designs, limiting efficiency.
• Need for compact, efficient optical components for microfluidic systems.

Purpose of the Study:

• To propose and design compact, efficient, integrated planar kinoform microlenses for microflow cytometry.
• To investigate the performance of these kinoform microlenses in focusing light within a microfluidic channel.
• To demonstrate the feasibility of fabricating and characterizing these integrated microlenses.

Main Methods:

• Detailed design procedure for paraxial kinoform lenses.
• Simulation of several kinoform lens designs.
• Fabrication of a kinoform lens integrated with a microfluidic channel in silicate glass.
• Characterization of focal position and spot size.

Main Results:

• Successfully designed and simulated kinoform microlenses.
• Fabricated a paraxial kinoform lens integrated with a microfluidic channel.
• Measured focal spot sizes of 5.6 μm.
• Achieved focal points as far as 56 μm into the microfluidic channel.

Conclusions:

• Integrated planar kinoform microlenses are a viable and efficient solution for optical detection in microflow cytometry.
• These microlenses enable precise focusing of light within microfluidic channels for improved microparticle analysis.
• The demonstrated fabrication and characterization pave the way for advanced microfluidic optical systems.