A new instrument for measuring light extinction by single accumulation mode particles

JS Walker, AE Carruthers, JP Reid & AJ Orr-Ewing

This work discusses the development of a powerful new tool for probing the optical properties of single accumulation mode aerosol particles. Individual particles are optically trapped and isolated using a vertically propagating Bessel beam and simultaneously characterised using cavity ring-down spectroscopy (CRDS) and elastically scattered light. The experiment allows controlled manipulation of a trapped particle through the CRDS beam to measure the optical extinction of the particle. A single laser source is used to provide both the optical trapping and CRDS light. We present the first controlled single aerosol particle CRDS measurements using this combined optical technique that allows the effect of hygroscopic size changes on the optical extinction of an aqueous sodium chloride particle to be measured.

Join today to view and download the full abstract/presentation