A CCD based approach to high-precision size and refractive index determination of levitated microdroplets using Fraunhofer diffraction

Barnes, Michael D.; Lermer, N.; Whitten, William B.; Ramsey, J. Michael

doi:10.1063/1.1148134

Cited by 46 publications

(30 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The particle radius was obtained from the analysis of interference fringes for light scattered from the trapping laser and collected over a known angular range (the phase function). [11][12][13] In the analysis described in section 5, the beam waist of the TEM00 mode was obtained as 279 m, which compares well to the value expected for our design of linear optical cavity of 272 m. 9 Experimental measurements are overlaid by Mie scattering calculations in (2) to account for the measurement of extinction by light scattering within an optical cavity.…”

Section: Extinction Cross Section Determination In An Optical Cavitymentioning

confidence: 56%

Deviations from Plane-Wave Mie Scattering and Precise Retrieval of Refractive Index for a Single Spherical Particle in an Optical Cavity

et al. 2014

View full text Add to dashboard Cite

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. (0)117 9287672 e-mail: a.orr-ewing@bristol.ac.uk AbstractThe extinction cross sections of individual, optically confined aerosol particles with radii of a micron or less can, in principle, be measured using cavity ring-down spectroscopy (CRDS). However, when the particle radius is comparable in magnitude to the wavelength of light stored in a high-finesse cavity, the phenomenological cross-section retrieved from a CRDS experiment depends on the location of the particle in the intra-cavity standing wave and differs from the Mie scattering cross section for plane-wave irradiation. Using an evaporating 1,2,6-hexanetriol particle of initial radius ~1.75 m confined within the 4.5-m diameter core of a Bessel beam, we demonstrate that the scatter in the retrieved extinction efficiency of a single particle is determined by its lateral motion, which spans a few wavelengths of the intra-cavity standing wave used for CRDS measurements. Fits of experimental measurements to Mie calculations, modified to account for the intra-cavity standing wave, allow precise retrieval of the refractive index of 1,2,6-hexanetriol particles (with relative humidity, RH < 10%) of 1.47824  0.00072.

show abstract

Section: Extinction Cross Section Determination In An Optical Cavitymentioning

confidence: 56%

Deviations from Plane-Wave Mie Scattering and Precise Retrieval of Refractive Index for a Single Spherical Particle in an Optical Cavity

et al. 2014

View full text Add to dashboard Cite

show abstract

“…One approach for inferring size is to perform a full Mie calculation of the angularly resolved elastically scattered light for comparison with the recorded phase function. Iterative fitting can then allow the size to be retrieved by minimizing the difference between the recorded and simulated phase functions, in a method similar to that of Barnes et al (1997). A less computationally demanding method that can be used to estimate droplet size as the measurement proceeds is based on the geometrical optics approximation (Glantschnig and Chen 1981).…”

Section: Estimating Droplet Sizementioning

confidence: 99%

Time-Resolved Measurements of the Evaporation of Volatile Components from Single Aerosol Droplets

Davies

Haddrell

Reid

2012

Aerosol Science and Technology

106

147

View full text Add to dashboard Cite

A strategy for examining the dynamic hygroscopic response of single aerosol particles is reported, allowing a direct investigation of the interplay of thermodynamic and kinetic factors regulating the time dependence of particle size. In particular, we investigate the rapid evaporation of water from water-glycerol droplets, measuring the evolving size with a time resolution of <10 ms (with as low as 2.5 ms being possible) over a time range from subsecond to many hours. Measurements can be made on sequential droplets generated from a droplet-on-demand generator, and a reproducibility of better than ±0.25 µm in droplet size over tens of events can be achieved at any resolved time point considered during an evaporation process lasting >2 s. The time-dependent measurements of evolving droplet size are compared with an analytical treatment of the evaporation process. Excellent agreement between measurements and simulations is found over a wide range of starting droplet compositions. The benefits of using this approach for investigating water transport within the bulk of an aerosol particle or to/from the droplet surface are discussed.

show abstract

“…Fig. 1 shows Fraunhofer diffraction data from three different poly(ethylene oxide) (PEO) microparticles, along with fits to the data using Mie theory 15) . The refractive index obtained from the data analysis is consistent with bulk (nominal) values for PEO, and the level of agreement with Mie theory indicates that the particles are nearly perfect spheres.…”

Section: Introduction and Methodsmentioning

confidence: 99%

Molecular dynamics simulation of the thermal properties of nano-scale polymer particles

Fukui¹,

Sumpter

Barnes

et al. 1999

Macromol. Theory Simul.

View full text Add to dashboard Cite

SUMMARY: Molecular dynamics simulations for nanometer scale polyethylene (PE) particles generated with up to 12000 atoms are presented to gain insight into some thermodynamic properties of ultra fine polymer powders. By computing molecular volume and total energy as a function of temperature, we obtained melting point, glass transition temperature, and heat capacity. The results of our simulations predict an interesting reduction of the melting point in comparison with the PE bulk system.

show abstract

A CCD based approach to high-precision size and refractive index determination of levitated microdroplets using Fraunhofer diffraction

Abstract: Articles you may be interested inDetermination of char combustion kinetics parameters: Comparison of point detector and imaging-based particlesizing pyrometry Rev. Sci. Instrum. 85, 075114 (2014); 10.1063/1.4890438Diffraction by electronic components of everyday use Am.

Cited by 46 publications

References 19 publications

Deviations from Plane-Wave Mie Scattering and Precise Retrieval of Refractive Index for a Single Spherical Particle in an Optical Cavity

Deviations from Plane-Wave Mie Scattering and Precise Retrieval of Refractive Index for a Single Spherical Particle in an Optical Cavity

Time-Resolved Measurements of the Evaporation of Volatile Components from Single Aerosol Droplets

Molecular dynamics simulation of the thermal properties of nano-scale polymer particles

Contact Info

Product

Resources

About