Digital holographic microscopy with reduced spatial coherence for three-dimensional particle flow analysis.

Area of Science:

• Optical microscopy
• Fluid dynamics
• Particle imaging

Background:

• Studying micrometer-size particle flow requires capturing dynamic, three-dimensional information.
• Traditional methods may struggle with the rapid variations inherent in particle flow phenomena.

Purpose of the Study:

• To investigate the application of digital holographic microscopy (DHM) under partially coherent illumination for 3D particle flow analysis.
• To develop and demonstrate a method for extracting complete holographic information for each camera frame.

Main Methods:

• Implementation of a digital holographic microscope with partially coherent illumination.
• Utilization of the Fourier-transform method for optical amplitude extraction.
• Employing a split-flow lateral-transport thin separation cell for particle suspension flow.

Main Results:

• Demonstration of reconstructed images for particles of varying sizes.
• Successful application of a particle-velocity measurement technique leveraging blurred holographic images.
• Acquisition of complete holographic data for each frame to analyze rapid variations.

Conclusions:

• Digital holographic microscopy with partial coherence is effective for 3D micrometer particle flow studies.
• The Fourier-transform method enables robust optical amplitude extraction for dynamic systems.
• The developed technique allows for particle size characterization and velocity measurement.