Individual and aggregate scattering matrices and cross-sections: Conservation laws and reciprocity

Stout, Brian; Auger, Jean-Claude; Lafait, J.

doi:10.1080/09500340108235502

Cited by 16 publications

(22 citation statements)

References 10 publications

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“…Although we aim at investigating the local electromagnetic field produced by the scattering of a homogeneous dielectric sphere, the fact that the spheres studied were all several wavelengths in diameter allows us to work in the context of general Mie theory [20]. Numerical simulations have thus been performed using the quasi-exact Mie theory [21,22] with analytic expressions for the incident, scattered, and internal fields on a basis of multipolar wave functions M and N [23]. This approach permits a ready calculation of the field at any point in space to arbitrary accuracy.…”

Section: Methodsmentioning

confidence: 99%

Direct imaging of photonic nanojets

Ferrand¹,

Wenger²,

Devilez³

et al. 2008

Opt. Express

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254

164

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We report the direct experimental observation of photonic nanojets created by single latex microspheres illuminated by a plane wave at a wavelength of 520 nm. Measurements are performed with a fast scanning confocal microscope in detection mode, where the detection pinhole defines a diffraction-limited observation volume that is scanned in three dimensions over the microsphere vicinity. From the collected stack of images, we reconstruct the full 3 dimensional photonic nanojet beam. Observations are conducted for polystyrene spheres of 1, 3 and 5 microm diameter deposited on a glass substrate, the upper medium being air or water. Experimental results are compared to calculations performed using the Mie theory. We measure nanojet sizes as small as 270 nm FWHM for a 3 microm sphere at a wavelength lambda of 520 nm. The beam keeps a subwavelength FWHM over a propagation distance of more than 3 lambda, displaying all the specificities of a photonic nanojet.

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Section: Methodsmentioning

confidence: 99%

Direct imaging of photonic nanojets

Ferrand¹,

Wenger²,

Devilez³

et al. 2008

Opt. Express

Self Cite

254

164

View full text Add to dashboard Cite

show abstract

“…We have previously established that the calculation of the τ ði;jÞ N matrices can be an efficient means of obtaining the T ðiÞ N matrices [11,12]. Thus, using the representations of the incident and scattered fields' expansions on the VSWFs, the total external field intensity can be expressed as…”

Section: Orientation Average Expression Of the Total External Fielmentioning

confidence: 99%

“…Furthermore, the local fields can be exactly evaluated at any point in space, whereas in finite element methods, their precision depends on the mesh size and the extrapolation function. An all-important advantage in the present context is that the multiple scattering T matrix formalism can yield analytical expressions for the orientation and polarization averages of both far field optical parameters [11] and the near field averages derived herein.…”

Section: Introductionmentioning

confidence: 99%

Local field intensity in aggregates illuminated by diffuse light: T matrix approach

Auger

Stout

2008

Appl. Opt.

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We derive an analytic expression for the local field intensity in an aggregate of particles illuminated by diffuse light (T matrix formalism). To be precise, the diffuse light average is obtained by averaging the electromagnetic response from plane waves over all possible incident field direction polarizations. We applied this new averaging formula to analyze variations in the electromagnetic couplings between two isotropic spheres as a function of their separation distance. The numerical calculations were performed with the recursive centered T matrix algorithm (RCTMA), one of the known analytical solutions of the multiple scattering equation of light. Illustrative calculations clearly demonstrate that diffuse averaging has a large smoothing effect on the strong angular and local variations in the field intensities that are omnipresent in orientation fixed calculations. We believe that this formalism can be a valuable tool in the analysis of electromagnetic couplings in dense random heterogeneous media, in which light propagation is dominated by a scalar diffusion behavior.

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“…(4) [16][17][18][19]. Once the N-scatterer T matrices have been deter-mined, the total cross sections of the N interacting particles can be easily calculated [20,21]. Finally, let us recall that in practice, the computation of the T 1 ͑i͒ matrices requires the truncation of an infinite-dimensional integral matrix equation to a value n = n max .…”

Section: ͑2͒mentioning

confidence: 99%

Absorption and scattering properties of dense ensembles of nonspherical particles

2007

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The purpose of this work is to show that an appropriate multiple T-matrix formalism can be useful in performing qualitative studies of the optical properties of colloidal systems composed of nonspherical objects (despite limitations concerning nonspherical particle packing densities). In this work we have calculated the configuration averages of scattering and absorption cross sections of different clusters of dielectric particles. These clusters are characterized by their refraction index, particle shape, and filling fraction. Computations were performed with the recursive centered T-matrix algorithm (RCTMA), a previously established method for solving the multiple scattering equation of light from finite clusters of isotropic dielectric objects. Comparison of the average optical cross sections between the different systems highlights variations in the scattering and absorption properties due to the electromagnetic interactions, and we demonstrate that the magnitudes of these quantities are clearly modulated by the shape of the primary particles.

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Individual and aggregate scattering matrices and cross-sections: Conservation laws and reciprocity

Cited by 16 publications

References 10 publications

Direct imaging of photonic nanojets

Direct imaging of photonic nanojets

Local field intensity in aggregates illuminated by diffuse light: T matrix approach

Absorption and scattering properties of dense ensembles of nonspherical particles

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