Meta-Lens Particle Image Velocimetry

Area of Science:

• Fluid Dynamics
• Optical Engineering
• Nanotechnology

Background:

• Traditional particle image velocimetry (PIV) systems require complex multi-camera setups.
• Conventional lenses in PIV systems are bulky and heavy.
• Meta-lenses offer ultrathin, compact, and aberration-free optical imaging solutions.

Purpose of the Study:

• To develop a compact and lightweight binocular PIV system using meta-lenses.
• To enable accurate 3D fluid velocity field measurements.
• To advance flow diagnostic tools for portable and space-constrained applications.

Main Methods:

• Fabrication of a pair of Gallium Nitride (GaN) meta-lenses on a single substrate.
• Integration of the meta-lenses with an imaging sensor to create a compact binocular PIV system.
• Utilizing binocular disparity and particle image displacement for 3D velocity reconstruction.

Main Results:

• The developed meta-lens PIV system weighs only 116 mg, significantly lighter than commercial lenses.
• Experimental validation using a Reynolds-number 2000 vortex-ring showed a measurement error of approximately 1.25% for vortex-ring diameter.
• Demonstrated the capability to obtain 3D velocity fields of fluid flow.

Conclusions:

• The binocular meta-lens PIV technique presents a significant advancement in flow diagnostic tools.
• This technology enables miniaturization and the development of low-power, easy-to-deploy PIV systems.
• The system is suitable for portable, field-use, and space-constrained PIV applications.