The point spread function in interferometric scattering microscopy (iSCAT). I. Aberrations in defocusing and axial localization

Abstract

Interferometric scattering (iSCAT) microscopy is an emerging label-free technique optimized for the sensitive detection of nano-matter. Previous iSCAT studies have approximated the point spread function in iSCAT by a Gaussian intensity distribution. However, recent efforts to track the mobility of nanoparticles in challenging speckle environments and over extended axial ranges has necessitated a quantitative description of the interferometric point spread function (iPSF). We present a robust vectorial diffraction model for the iPSF in tandem with experimental measurements and rigorous FDTD simulations. We examine the iPSF under various imaging scenarios to understand how aberrations due to the experimental configuration encode information about the nanoparticle. We show that the lateral shape of the iPSF can be used to achieve nanometric three-dimensional localization over an extended axial range on the order of 10$\mu$m either by means of a fit to an analytical model or calibration-free unsupervised machine learning. Our results have immediate implications for three-dimensional single particle tracking in complex scattering media.

References in corpus (5)

• Characterizing and tracking single colloidal particles with video holographic microscopy
• Light Microscopy: An ongoing contemporary revolution
• Machine Learning Holography for 3D Particle Field Imaging
• Interferometry of a Single Nanoparticle Using the Gouy Phase of a Focused Laser Beam
• Large depth-of-field tracking of colloidal spheres in holographic microscopy by modeling the objective lens

Cited by in corpus (8)

• Operando optical tracking of single-particle ion dynamics and phase transitions in battery electrodes
• Fundamental bounds on the precision of iSCAT, COBRI and dark-field microscopy for 3D localization and mass photometry
• Multiscale Modeling and Analysis for High-fidelity Interferometric Scattering Microscopy
• Direct Observation of Ultrafast Singlet Exciton Fission in Three Dimensions
• Point spread function engineering for spiral phase interferometric scattering microscopy enables robust 3D single-particle tracking
• Axial Profiling of Interferometric Scattering Enables an Accurate Determination of Nanoparticle Size
• Precise characterization of nanometer-scale systems using interferometric scattering microscopy and Bayesian analysis
• Interferometric Mass Photometry at the Quantum Limit of Sensitivity