A5050862807- Atmospheric chemistry and aerosols
- Orbital Angular Momentum in Optics
- Atmospheric aerosols and clouds
- Microfluidic and Bio-sensing Technologies
- Particle Dynamics in Fluid Flows
- Atmospheric Ozone and Climate
- Digital Holography and Microscopy
- Electrostatics and Colloid Interactions
- Oil Spill Detection and Mitigation
- Spectroscopy and Quantum Chemical Studies
- Surfactants and Colloidal Systems
ETH Zurich
2015-2020
A broadband light scattering experiment for the characterization of size and refractive index single submicron-to-micron sized aerosol particles is presented.
This study reveals that complex multiple processes occur during efflorescence and deliquescence in unsupported, submicron sized particles.
Abstract Many processes taking place in atmospheric aerosol particles are accompanied by changes the particles’ morphology (size and shape), with potentially significant impact on weather climate. However, characterization of dynamic information particle position over multiple time scales from microseconds to days under atmospherically relevant conditions has proven very challenging. Here we introduce holographic imaging unsupported air that spatially confined optical traps. Optical trapping...
We report the photodegradation of optically trapped oleic acid droplets by visible light in absence additional reactive gaseous species. The temporal evolution droplet's chemical composition and size is monitored Raman spectroscopy elastic scattering, respectively. dependencies on oxygen amount surrounding gas phase (~0–20%), droplet (~500–3000 nm radius), laser power wavelength are investigated. have only a very minor influence reaction rate, if at all. By contrast, becomes substantially...
Abstract Optical traps are used to isolate and manipulate small objects in air liquids, enabling the thorough characterization of their properties situ. However, no broadly applicable technique for mass measurements optically trapped is currently available. Here we propose an optical balance aerosol particles. By analyzing light-induced harmonic oscillations a particle, its determined non-destructively with high accuracy on time scale seconds. Its performance demonstrated aqueous salt...
We report on the dynamics of aerosol droplets in optical traps under influence additional constant and pulsed external forces. Experimental results are compared with simulations three-dimensional droplet for two types traps, counter-propagating Bessel beam (CPBB) trap quadruple (QBB) trap. Under a gas flow (constant force), QBB is found to be more stable CPBB By contrast, laser excitation pulse durations nanoseconds (pulsed type minor importance stability. It typically needs forces that...
In this contribution we present experiments used to control and characterize single optically trapped aerosol particles. These include a counter-propagating optical tweezer, feedback mechanism stabilize the particle in trap two-angle scattering measurement monitor time-evolution of size. Experimental setups results are presented for these experiments.
Nonspherical particles play a key role in the atmosphere by affecting processes such as radiative forcing, photochemistry, new particle formation and phase transitions. In this context, measurements on single proved to be very useful for detailed investigations of properties studied them. However, nonspherical are limited difficulties lack understanding associated with optical trapping particles. Here, we aim at better air comparing motion an observed simulated forces torques. An holographic...