Sizing of individual optically levitated evaporating droplets by measurement of resonances in the polarization ratio

Lettieri, Thomas R.; Jenkins, Wilhelmina D.; Swyt, Dennis A.

doi:10.1364/ao.20.002799

Cited by 45 publications

(18 citation statements)

References 13 publications

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“…In Appendix B we show, by analytically solving the integral in Eq. (12), that the resulting expressions for ͗F sca ͘ are indeed equal to Ϫ͗F out ͘. We will continue to show how the calculation of the forces can be formulated as a discrete convolution, thus allowing an O(N log N) calculation of the forces.…”

Section: Theory Of Radiation Forces In the Discrete-dipole Approximationmentioning

confidence: 90%

“…27 It can also be calculated by integrating the far-field scattered intensity, i.e., by removing the factor n in the integrand of Eq. (12). This integral can be solved analytically in the same way as we did for the scattering force and is equal to the exact result obtained from the extinction cross section and the absorption cross section.…”

Section: Appendix Bmentioning

confidence: 98%

“…(26), and also by integration of the scattered field, i.e., by applying Eq. (12). In the latter case a two-dimensional version of the Romberg integration method is applied.…”

Section: Tests On Spheresmentioning

confidence: 99%

“…In this way, scattering of a single evaporating water droplet was measured, experimentally demonstrating very sharp resonances in Mie scattering. 12 Furthermore, the differential scattering cross sections of single spheres (e.g., Ref. 13) and of single biological cells 14 were measured.…”

Section: Introductionmentioning

confidence: 99%

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Radiation forces in the discrete-dipole approximation

et al. 2001

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The theory of the discrete-dipole approximation (DDA) for light scattering is extended to allow for the calculation of radiation forces on each dipole in the DDA model. Starting with the theory of Draine and Weingartner [Astrophys. J. 470, 551 (1996)] we derive an expression for the radiation force on each dipole. These expressions are reformulated into discrete convolutions, allowing for an efficient, O(N log N) evaluation of the forces. The total radiation pressure on the particle is obtained by summation of the individual forces. The theory is tested on spherical particles. The resulting accumulated radiation forces are compared with Mie theory. The accuracy is within the order of a few percent, i.e., comparable with that obtained for extinction cross sections calculated with the DDA.

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Section: Theory Of Radiation Forces In the Discrete-dipole Approximationmentioning

confidence: 90%

Section: Appendix Bmentioning

confidence: 98%

“…(26), and also by integration of the scattered field, i.e., by applying Eq. (12). In the latter case a two-dimensional version of the Romberg integration method is applied.…”

Section: Tests On Spheresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Radiation forces in the discrete-dipole approximation

et al. 2001

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“…Another technique for larger particles consists of the measurement of resonances in the polarization ratio of scattered light. Lettieri et al [33] measured the diameter of droplets in thF size range 6 to 12 pum to a resolution of 0.003 ptm using this technique.…”

Section: Electrical Sensing Zone-counter Measurementsmentioning

confidence: 99%

Development of a one-micrometer-diameter particle size Standard Reference Material

Mulholland

Hartman

Hembree

et al. 1985

J. RES. NATL. BUR. STAN.

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The average diameter of the first micrometer particle size standard (Standard Reference Material 1690), an aqueous suspension of monosized polystyrene spheres with a nominal gum diameter, was accurately determined by three independent techniques. In one technique the intensity of light scattered by a diluted suspension of polystyrene spheres was measured as a function of scattering angle, using a He-Ne laser polarized in the vertical direction. The second technique consisted of measuring as a function of angle the intensity of light scattered from individual polystyrene spheres suspended in air, using a He-Cd laser with light polarized parallel and perpendicular to the scattering plane. The measurement of row length by optical microscopy for polystyrene spheres arranged in close-packed, two-dimensional hexagonal arrays was the basis of the third technique. The measurement errors for each technique were quantitatively assessed. For the light scattering experiments, this required simulation with numerical experiments. The average diameter determined by each technique agreed within 0.5% with the most accurate value being 0.895±0.007 gm based on light scattering by an aqueous suspension. Transmission electron microscopy, flow through electrical sensing zone counter measurements, and optical microscopy were also used to obtain more detailed information on the size distribution including the standard deviation (0.0095 gum), fraction of off-size particles, and the fraction of agglomerated doublets (1.5%).

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Morphology Dependent Resonances in Raman Spectra of Optically Levitated Microparticles: Determination of Radius and Evaporation Rate of Single Glycerol/Water Droplets by means of Internal Mode Assignment

Schaschek

Popp

Kiefer

1993

Ber Bunsenges Phys Chem

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An experimental setup for studies of morphology dependent resonances (MDRs) in Raman spectra of optically levitated microdroplets is described. This instrumentation is used for the study of MDRs in the Raman spectra of glycerol/water (3 : 1) droplets. Furthermore we show how the MDRs observed in the Raman spectra and their change with time can be used to determine the radius and the index of refraction of single optically levitated droplets with very high accuracy. We further show how the results of this study can be used to calculate the efficiency factor of the radiation pressure and compare it with the experimental monitored laser power.

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Sizing of individual optically levitated evaporating droplets by measurement of resonances in the polarization ratio

Cited by 45 publications

References 13 publications

Radiation forces in the discrete-dipole approximation

Radiation forces in the discrete-dipole approximation

Development of a one-micrometer-diameter particle size Standard Reference Material

Morphology Dependent Resonances in Raman Spectra of Optically Levitated Microparticles: Determination of Radius and Evaporation Rate of Single Glycerol/Water Droplets by means of Internal Mode Assignment

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