title: Holographic tracking and sizing of optically trapped microprobes in diamond anvil cells.
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.
authors.forename: F
authors.initials: F
authors.lastname: Saglimbeni
authors.forename: S
authors.initials: S
authors.lastname: Bianchi
authors.forename: G
authors.initials: G
authors.lastname: Gibson
authors.forename: R
authors.initials: R
authors.lastname: Bowman
authors.forename: M
authors.initials: M
authors.lastname: Padgett
authors.forename: R
authors.initials: R
authors.lastname: Di Leonardo