The question of how to relate particle sizes measured using a fixed-angle dynamic light scattering (DLS) instrument with those measured using a multi-angle DLS instrument is addressed. A series of nearly monodisperse polystyrene latex (PSL) particles with nominal diameters of 100 nm, 70 nm, 50 nm, and 30 nm were measured using two different types of DLS instruments: one owned by the National Metrology Institute of Japan (NMIJ) of the multi-angle type and the other owned by the National Institute of Standards and Technology (NIST) of the fixed-angle type. The mean particle size of the PSL particles was measured using the multi-angle-type instrument at various scattering angles and at various concentrations of particle suspension.
View Article and Find Full Text PDFAtomic force microscopes (AFMs) are commonly and broadly regarded as being capable of three-dimensional imaging. However, conventional AFMs suffer from both significant functional constraints and imaging artifacts that render them less than fully three dimensional. To date a widely accepted consensus is still lacking with respect to characterizing the spatial dimensions of various AFM measurements.
View Article and Find Full Text PDFThe cyclic error of a homodyne interferometer is caused mainly by phase mixing due to the imperfection of polarizing optical components such as polarizing beam splitters. In Appl. Opt.
View Article and Find Full Text PDFMost homodyne interferometers have a quadrature detector system that includes two polarizing beam splitters that cause nonlinearity of the order of a few nanometers by phase mixing. Detectors should have the same gains to reduce nonlinearity under the assumption that there is no loss in optical components. However, optical components exhibit some loss.
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