title: Angular-domain scattering interferometry.
abstract: We present an angular-scattering optical method that is capable of measuring the mean size of scatterers in static ensembles within a field of view less than 20 μm in diameter. Using interferometry, the method overcomes the inability of intensity-based models to tolerate the large speckle grains associated with such small illumination areas. By first estimating each scatterer's location, the method can model between-scatterer interference as well as traditional single-particle Mie scattering. Direct angular-domain measurements provide finer angular resolution than digitally transformed image-plane recordings. This increases sensitivity to size-dependent scattering features, enabling more robust size estimates. The sensitivity of these angular-scattering measurements to various sizes of polystyrene beads is demonstrated. Interferometry also allows recovery of the full complex scattered field, including a size-dependent phase profile in the angular-scattering pattern.
authors: Dustin W
authors: DW
authors: Shipp
authors: Ruobing
authors: R
authors: Qian
authors: Andrew J
authors: AJ
authors: Berger
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007368:Interferometry / Q000295:instrumentation*; D007909:Lenses; D008027:Light; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation