Application of a shaped, divergent Laser Beam for the optical measurement of the size and density of ambient particulate matter

In optical particle detection systems the size of particles can easily be determined, e.g. from the scattered light, when the refractive index of the particle is known [1]. However, no information on the particle density or mass can be obtained. This information is especially interesting as environmental safety standards still consider the particle mass only. In our work we show a new method to measure particle size and mass based on a shaped, divergent laser beam using the inertia-dependent particle movement inside an optical measurement chamber.