New techniques to retrieve optical constans from single levitated particles

New techniques to retrieve optical constans from single levitated particles
14
Oct

Se invita a toda la comunidad universitaria al siguiente seminario:

Título: New techniques to retrieve optical constans from single levitated particles

Ponente: Dr. Antonio Valenzuela, Investigador de la Universidad de Granada

Lugar: Salón de Conferencias del Instituto Interuniversitario de Investigación del Sistema Tierra en Andalucía

Día y hora: viernes 14 de junio de 2019, a las 13:00

Resumen:

Aerosols constitute one of the main climate change agents. According to the Fifth Assessment Report (AR5) of the last Intergovernmental 
Panel on Climate Change (IPCC) in 2013, atmospheric aerosol produces a net cooling effect of the Earth’s climate. However, an accurate estimate of this 
cooling is extremely difficult because of the large uncertainty on the estimation of the aerosol radiative forcing (RF), where the largest uncertainty 
in RF is due to uncertainties in understanding aerosol properties. Reduction of these uncertainties requires improved methods of laboratory determination of 
the optical properties of aerosol particles and their change with ambient relative humidity. Cavity ring-down spectroscopy (CRDS) has been proven to be a sensitive tool 
for measuring the absolute extinction cross-sections for single aerosol particles with high precision by combining optical confinement and levitation of a particle with 
CRDS. We present a new experimental approach which levitates single particles, confined within optical or electrodynamic traps, providing precise measurements of aerosol 
refractive indices, hygroscopic growth and other properties of importance for their atmospheric behavior.