Application of Newton’s Zero Order Caustic for Analysis and Measurement: Part III – Light Scattering

When light is incident upon a liquid suspension that has an oblate spheroid shape, the size and presence of particles can be determined by measuring light intensity exiting the sample or by imaging the scattered light using a digital camera. This dual analysis system is facilitated by Newton’s zero order caustic formed within the sample, which creates a region of high intensity light inside the spheroid. Refraction of light exiting the spheroid directs a high percentage of scattered light near the zone of highest incident light intensity, which increases specific turbidity changes with particle size and facilitates analysis of gold nanoparticle plasmon resonance. Images taken with an ordinary digital camera at 90 degrees from the incident light can be analyzed using spatial autocorrelation in order to detect particle size.