Abstract
We demonstrate that Digital Holographic Microscopy can be used for accurate 3D tracking and sizing of a colloidal probe trapped in a diamond anvil cell (DAC). Polystyrene beads were optically trapped in water up to Gigapascal pressures while simultaneously recording in-line holograms at 1 KHz frame rate. Using Lorenz-Mie scattering theory to fit interference patterns, we detected a 10% shrinking in the bead's radius due to the high applied pressure. Accurate bead sizing is crucial for obtaining reliable viscosity measurements and provides a convenient optical tool for the determination of the bulk modulus of probe material. Our technique may provide a new method for pressure measurements inside a DAC.
Highlights
Digital holographic microscopy (DHM) can be used in combination with Mie scattering theory to simultaneously track and characterize colloidal particles with nanometer resolution [1]
Using a mirror trap configuration [9, 10] and a diamond anvil cell (DAC) [11] we have recently shown that the full power of holographic tweezers can be made available for high pressure studies [12, 13]
The DAC chamber has been loaded with 5 μm polystyrene beads (Bangs Laboratories) dispersed in deionized water
Summary
Digital holographic microscopy (DHM) can be used in combination with Mie scattering theory to simultaneously track and characterize colloidal particles with nanometer resolution [1]. Holographic optical tweezers (HOT) [3,4,5] offer a powerful tool for microrheological studies [6,7,8] and, when combined with DHM, allow for a full 3D and multipoint particle tracking for viscosity measurements [2]. The technique requires the a priori knowledge of the probe’s diameter which is usually provided by the manufacturer with a standard deviation ranging from 3% to 15%. This fact prevents accurate viscosity measurements leading to systematic errors of the order of a few percent
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
