High-speed plenoptic imaging attachment for 3D microfluidic velocimetry on standard inverted microscopes

We present a high-speed plenoptic imaging attachment that transforms a standard Nikon inverted microscope into a snapshot three-dimensional imager for microfluidic flow diagnostics. Building on previous work with custom plenoptic 3.0 (p3.0) microscopes, this modular attachment enables single-exposure volumetric imaging without the need for scanning or multiple cameras. Despite its modular plug-in design, it achieves near-diffraction-limited 3D resolution (~2 μm) at over 800 fps, with particle positions localized to below the imaging wavelength. Both Lagrangian particle tracking (LPT) using "Shake-The-Box" (STB) and volumetric intensity reconstruction via Richardson-Lucy deconvolution are demonstrated in a 230 μm × 40 μm volume. This approach greatly simplifies the deployment of 3D microfluidic velocimetry while maintaining the resolution and precision of more complex multi-camera systems.