Abstract
We demonstrate the use of low spatial and temporal coherence holography microscopy, based on the Lorenz-Mie model, using the standard tungsten-halogen lamp present in an inverted microscope. An optical model is put forward to incorporate the effect of spectral width and different incidence angles of the incident light determined by the aperture at the back focal plane of the condenser lens. The model is validated for 899 nm diameter polystyrene microspheres in glycerol, giving a resolution of 0.4% for the index of refraction and 2.2% for the diameter of the particles.
Highlights
The hologram detected at the camera is the same hologram evaluated on the focal plane, apart from a magnification factor determined by the microscope setup
6.1 Influence of corrections To study the influence of the corrections made to the optical model for the calculation of the scattering hologram the analysis of a video is presented here with the various corrections applied or not
Holographic video microscopy based on fitting of Lorenz-Mie scattering profiles can be considered a very powerful tool to track spherical particles in 3D
Summary
Accurate and precise characterization of spherical colloidal particles is an important method in research fields such as biosensing [1,2,3,4,5,6,7], microscopy techniques [8,9,10,11], fluid flow tracing [12,13], the study of elektrokinetic effects with tracer particles [14] and food monitoring [15,16,17]. In the last decade holographic video microscopy based on fitting the acquired particle images to simulated Lorenz-Mie scattering holograms has proven to allow accurate characterization of single spherical particles with high resolving power This microscopecompatible method is able to capture time-dependent information on the position of individual spheres in three dimensions, on the particle’s diameter and on its refractive index. Using a highly coherent and powerful laser beam allows to generate a near-planar incident light field over a large field of view, to obtain a high hologram contrast, and to use short exposure times to avoid blurring related to particle movement (e.g. due to Brownian motion or drift) The technique makes it possible to detect biochemical reactions on polymer bioprobes such as avidin-biotin reaction [6], to estimate the porosity of single particles [24], and to inspect the quality of milk [16] and protein aggregates [25]. Thereafter the method is tested to verify if the particle’s properties correspond to the values provided by the manufacturer
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
