Imaging of phase transitions in single levitated aerosol particles using digital in-line holography

The physicochemical properties of aerosol particles such as size, shape, phase, and chemical composition are key factors influencing their interaction with sunlight as well as their uptake by the respiratory system. Many particles found in the Earth’s atmosphere are produced from sea spray and exhibit complex behavior and substantial changes in their properties in response to changing environmental factors like relative humidity or exposure to sunlight. In this contribution, we present a novel approach for imaging the dynamic particle properties using digital in-line holography on single, levitated aerosol particles. Optical tweezers are used to isolate single particles. The dynamics of the particle properties are recorded using Raman spectroscopy, broadband light scattering, and in-line holography. Through in-line holography, direct imaging of the size, shape, and phase of single particles is possible.