Method and system for measuring porosity of particles

A method of analyzing a particle in suspension, comprising the steps of:

• providing a video holographic microscope;
• providing a laser source for producing a collimated output beam comprised of a plurality of different wavelengths of light;
• scattering the collimated output beam off the particle by simultaneously using the plurality of different wavelengths of light to generate a plurality of scattered beams and a combination of the scattered beams and an unscattered portion of the output beam to generate a plurality of interference patterns;
• recording intensity of the interference pattern;
• analyzing the interference patterns through application of a Lorenz-Mie formalism to determine at least one of the refractive index of the particle and the medium disposed in the porosity of the particle wherein the Lorenz-Mie formalism comprises,
• I(r)=|E0(r)+E0(rp)fs(k(r−rp))|2,
• where I(r) is intensity of the interference pattern recorded at position r, E0(r) is the electric field of the output laser at position r, rp is the position of the particle, k is the wavenumber of the light, and fs(kr) is the Lorenz-Mie scattering function that describes scattering of light by the particle, wherein the Lorenz-Mie scattering function depends on radius of the particle, ap, and on effective refractive index np of the particle;
• and
• determining a measure of at least one of porosity of the particle and a medium disposed in the porosity of the particle.