Optical Particle Characterization

Onofri, Fabrice; Barbosa, Séverine

doi:10.1002/9781118576847.ch2

Cited by 7 publications

(5 citation statements)

References 120 publications

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“…A LES set-up comes in various forms (Deepak & Box 1978 a ; Crawley et al. 1997; Xu 2001; Onofri & Barbosa 2012 b ; Glasse et al. 2015).…”

Section: Summary Of Light Extinction Spectroscopy (Les) Methodsmentioning

confidence: 99%

“…A LES set-up comes in various forms (e.g. (Xu 2001;Onofri & Barbosa 2012b;Glasse et al 2015;Deepak & Box 1978a;Crawley et al 1997)). To give an illustration of a typical set-up, the authors present below their own diagnostic, see a schematic view on Figure 9.…”

Section: Basic Experimental Set-up and Software Requirementsmentioning

confidence: 99%

“…Summary of light extinction spectroscopy (LES) method 2.1. Physical basis and basic equations LES consists in analysing the variations of the spectral transmittance of a broadband and collimated light beam passing through the particle cloud to be characterised (Bohren & Huffman 1998;Xu 2001;Onofri & Barbosa 2012b), see figure 2.…”

Section: Introductionmentioning

confidence: 99%

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An introduction to light extinction spectrometry as a diagnostic for dust particle characterisation in dusty plasmas

et al. 2016

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In this article, a detailed introduction of the light extinction spectrometry (LES) diagnostics is given. LES allows the direct in situ measurement of the particle size distribution and absolute concentration of dust clouds levitating in plasmas. Using a relatively simple and compact experimental set-up, the dust cloud parameters can be recovered with a good accuracy making minimum assumptions on their physical properties. Special emphases are given to the inversion procedure of light extinction spectra and all the required particle shape, refractive index and light extinction models. The parameter range and the limitations of LES are discussed. Two measurements in low-pressure gas discharges are presented: (i) in a direct-current (DC) glow discharge in which nanoparticles are growing from the sputtering of a tungsten cathode and (ii) in an argon–silane radio-frequency discharge. They demonstrate the capabilities of the LES technique to characterise, in situ and in real-time, the growth dynamics of nanoparticles in the size range 5–100 nm and volume concentrations in the range from a few ppb to a few ppm.

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“…A LES set-up comes in various forms (Deepak & Box 1978 a ; Crawley et al. 1997; Xu 2001; Onofri & Barbosa 2012 b ; Glasse et al. 2015).…”

Section: Summary Of Light Extinction Spectroscopy (Les) Methodsmentioning

confidence: 99%

Section: Basic Experimental Set-up and Software Requirementsmentioning

confidence: 99%

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An introduction to light extinction spectrometry as a diagnostic for dust particle characterisation in dusty plasmas

et al. 2016

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“…The NP cloud dynamics was studied using the laserlight-sheet scattering method [29,30]. A vertical laser sheet of 2 cm height (40 mW, wavelength λ L = 532 nm, linear polarisation at 45 • with respect to the horizontal plane (i.e.…”

Section: Laser-light-sheet Scattering Methodsmentioning

confidence: 99%

In-situcharacterisation of the dynamics of a growing dust particle cloud in a direct-current argon glow discharge

Barbosa¹,

Couëdel²,

Arnas³

et al. 2015

J. Phys. D: Appl. Phys.

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The growth and the dynamics of a tungsten nanoparticle cloud were investigated in a direct-current low pressure argon glow discharge. Real-time analyses of the dust particle size and number concentration were performed insitu by light extinction spectrometry, while spatial dynamics of the cloud was investigated with the laser light-sheet scattering method. Additional off-line electron microscopy and Raman spectroscopy measurements were also performed for comparison purpose. This experimental work reveals the existence of an agglomeration phase followed by the appearance of a new dust particle generation. While growing, the dust cloud is pushed towards the anode and the discharge edge. Afterwards, a new dust particle generation can grow in the space freed by the first generation of nanoparticles. The continuous growth, below the light extinction spectrometry scanning positions, explains the apparent dissimilarities observed between the in-line optical and the off-line electron microscopy analyses.

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“…Cylinders with non-circular geometrical cross-sections are encountered in various applications in electromagnetic (EM)/optical scattering [1][2][3][4][5], particle characterization [6] and manipulation, and computer visualization and graphics [7] to name a few areas. They received significant interest from the standpoint of optical scattering theory in elliptical coordinates [8,9], cylindrical coordinates [10], and vector complex ray modeling [11].…”

Section: Introductionmentioning

confidence: 99%

Optical radiation force (per–length) on an electrically conducting elliptical cylinder having a smooth or ribbed surface

Mitri¹

2019

OSA Continuum

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The aim of this work is to develop a formal semi-analytical model using the modal expansion method in cylindrical coordinates to calculate the optical/electromagnetic (EM) radiation force-per-length experienced by an infinitely long electrically-conducting elliptical cylinder having a smooth or wavy/corrugated surface in EM plane progressive waves with different polarizations. In this analysis, one of the semi-axes of the elliptical cylinder coincides with the direction of the incident field. Initially, the modal matching method is used to determine the scattering coefficients by imposing appropriate boundary conditions and solving numerically a linear system of equations by matrix inversion. In this method, standard cylindrical (Bessel and Hankel) wave functions are used. Subsequently, simplified expressions leading to exact series expansions for the optical/EM radiation forces assuming either electric (TM) of magnetic (TE) plane wave incidences are provided without any approximations, in addition to integral equations demonstrating the direct relationship of the radiation force with the square of the scattered field magnitude. An important application of these integral equations concerns the accurate determination of the radiation force from the measurement of the scattered field by any 2D non-absorptive object of arbitrary shape in plane waves. Numerical computations for the non-dimensional radiation force function are performed for electrically conducting elliptic and circular cylinders having a smooth or ribbed/corrugated surface. Adequate convergence plots confirm the validity and correctness of the method to evaluate the radiation force with no limitation to a particular frequency range (i.e. Rayleigh, Mie or geometrical optics regimes). Particular emphases are given on the aspect ratio, the non-dimensional size of the cylinder, the corrugation characteristic of its surface, and the polarization of the incident field. The results are particularly relevant in optical tweezers and other related applications in fluid dynamics, where the shape and stability of a cylindrical drop stressed by a uniform external electric/magnetic field are altered. Furthermore, a direct analogy with the acoustical counterpart is noted and discussed.

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Optical Particle Characterization

Cited by 7 publications

References 120 publications

An introduction to light extinction spectrometry as a diagnostic for dust particle characterisation in dusty plasmas

An introduction to light extinction spectrometry as a diagnostic for dust particle characterisation in dusty plasmas

In-situcharacterisation of the dynamics of a growing dust particle cloud in a direct-current argon glow discharge

Optical radiation force (per–length) on an electrically conducting elliptical cylinder having a smooth or ribbed surface

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