Ultraviolet broadband light scattering for optically-trapped submicron-sized aerosol particles

Area of Science:

• Aerosol science
• Optical physics
• Spectroscopy

Background:

• Characterizing individual aerosol particles is crucial for atmospheric studies and material science.
• Existing methods often lack the precision or spectral range to fully determine optical properties of submicron particles.

Purpose of the Study:

• To develop and validate a broadband light scattering technique for accurate size and refractive index determination of single aerosol particles.
• To extend characterization capabilities to the ultraviolet (UV) spectral region.

Main Methods:

• Utilizing a quadruple Bessel beam optical trap or optical tweezers to isolate single aerosol particles.
• Employing broadband radiation from 320 to 700 nm for light scattering measurements.
• Analyzing scattering patterns to retrieve particle size and wavelength-dependent refractive index.

Main Results:

• Accurate sizing of submicron particles (down to 300 nm radius) with nanometer precision.
• Determination of refractive index with an uncertainty of approximately 0.01.
• Acquisition of wavelength-dependent refractive index data, including the UV range.

Conclusions:

• The broadband light scattering setup provides a robust method for comprehensive single aerosol particle characterization.
• The technique is versatile, demonstrated by applications in sizing, phase transitions, and chemical reactions of various aerosols.