Off-axis digital holographic particle positioning based on polarization-sensitive wavefront curvature estimation
Number of Authors: 2
2016 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 55, no 27, 7503-7510 p.Article in journal (Refereed) Published
Poor axial resolution in holographic particle imaging applications makes particle positioning in 3D space morecomplex since the positions are not directly obtained. In this paper we estimate the axial position of micrometerparticles by finding the location where the wavefront curvature from the scattered light becomes zero. By record-ing scattered light at 90°using off-axis holography, the complex amplitude of the light is obtained. Byreconstruction of the imaged scene, a complex valued volume is produced. From this volume, phase gradientsare calculated for each particle and used to estimate the wavefront curvature. From simulations it is found that thewavefront curvature became zero at the true axial position of the particle. We applied this metric to track an axialtranslation experimentally using a telecentric off-axis holographic imaging system with a lateral magnification ofM1.33. A silicon cube with molded particles inside was used as sample. Holographic recordings are performedboth before and after a 100μm axial translation. From the estimated positions, it was found that the mean dis-placement of particles between recordings was 105.0μm with a standard deviation of 25.3μm.
Place, publisher, year, edition, pages
Optical Society of America, 2016. Vol. 55, no 27, 7503-7510 p.
Digital holography, Scattering, Particles
Research subject Experimental Mechanics
IdentifiersURN: urn:nbn:se:ltu:diva-59662DOI: 10.1364/AO.55.007503ISI: 000383996900008ScopusID: 2-s2.0-84988878500OAI: oai:DiVA.org:ltu-59662DiVA: diva2:1034170
FunderSwedish Research Council, 621-2014-4906
Validerad; 2016; Nivå 2; 2016-10-25 (andbra)2016-10-112016-10-112017-01-19Bibliographically approved