Dynamic 3D light scattering particle size distribution with offset polarization beams

A dynamic 3D light scattering particle size distribution measurement device, comprising:

• (a) a laser light source for emitting a laser beam,
• (b) a polarization splitter for generating
• (i) an s laser beam with perpendicular polarization, and
• (ii) a p laser beam with parallel polarization that travels parallel to the s laser beam, wherein the p laser beam is spaced apart from the s laser beam by a beam spacing other than zero,
• (c) a sample holder for holding a sample whose particle size distribution is to be measured,
• (d) a lens that focuses the s laser beam and the p laser beam onto a common focus area inside the sample holder,
• (e) an s light intensity detector for measuring a time-resolved s light intensity, wherein the s light intensity detector
• (i) is arranged to detect an s backscattered light beam from backscattered light of the s laser beam from the focus area,
• (ii) comprises an s-polarisation filter that allows perpendicularly polarized light to pass, resulting in s measuring light, and
• (iii) comprises a light detector for time-resolved intensity measurement of the s measuring light,
• (f) a p light intensity detector for measuring a time-resolved p light intensity, wherein the p light intensity detector
• (i) is arranged to detect a p backscattered light beam from backscattered light of the p laser beam from the focus area,
• (ii) comprises a p polarization filter that allows parallel polarized light to pass, resulting in p measuring light, and
• (iii) comprises a light detector for time-resolved intensity measurement of the p measuring light, and
• (g) an evaluation unit designed to automatically calculate particle size distribution from a time correlation function of the time-resolved p light intensity and the time-resolved s light intensity.