Super-Resolution Defocusing Nanoparticle Image Velocimetry Utilizing Spherical Aberration for Nanochannel Flows

Area of Science:

• Nanofluidics
• Optical Physics
• Analytical Chemistry

Background:

• Understanding fluid dynamics and mass transport in nanoscale environments is crucial for developing advanced nanofluidic devices.
• Existing particle tracking methods face limitations in resolving nanoscale phenomena.

Purpose of the Study:

• To develop a super-resolution, fast particle tracking method for precise nanochannel flow measurement.
• To optimize optical parameters for enhanced spatial resolution beyond the diffraction limit.

Main Methods:

• Utilized defocusing images with spherical aberration to determine nanoparticle position from diffraction ring radius.
• Investigated and optimized optical system components for improved spatial resolution.
• Confirmed negligible impact of sub-wavelength nanoparticles on image quality and resolution.

Main Results:

• Achieved a spatial resolution of 19 nm and temporal resolution of 160 μs under optimized conditions.
• Successfully measured pressure-driven flow in a 370 nm nanochannel using 67 nm fluorescent nanoparticles.
• Observed a parabolic velocity profile with slip at the surface, consistent with Hagen-Poiseuille law.

Conclusions:

• The developed super-resolution particle tracking method is effective for nanochannel flow analysis.
• This technique offers significant advancements for research in nanofluidics and related fields.
• The method provides high spatial and temporal resolution, crucial for understanding nanoscale transport phenomena.