Differential dynamic microscopy with light field microscopy for quantifying dynamics in 3D

Understanding the 3D dynamics of soft materials has applications ranging from material science to pharmaceutical research. While optical microscopy methods exist to reveal 3D information, they are often expensive or computationally costly and elaborate. Existing light field microscopy (LFM) techniques can reconstruct 3D structures based on 2D LFM images, but their reconstruction algorithms can be prohibitively time-consuming for use in the analysis of dynamics which typically requires movies that encompass a range of time scales. To bypass this computational cost, we directly analyze 2D LFM images with adaptations of differential dynamic microscopy and single particle tracking, image analysis techniques traditionally used to study the dynamics of 2D systems. The integrated technique allows measurement of 3D dynamics with an unprecedented low setup cost and swift computation. We demonstrate the ability of our technique to measure the dynamics of samples of micron-sized colloidal beads undergoing a variety of combinations of diffusive and ballistic motion.