Scattering and localization of light on fractals

Shalaev, Vladimir M.; Moskovits, Martin; Golubentsev, A. A.; John, Sajeev

doi:10.1016/0378-4371(92)90551-z

Cited by 22 publications

(10 citation statements)

References 8 publications

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“…[36,37] Those works have shown the importance of stochastic fractals having self-similar properties over multiple length scales, in improving the localization of electromagnetic energy in subwavelengths volumes. [18] The hierarchical features of Au-TiO 2 fractals, along with a high porosity (up to 98%) achieved in the DLA regime, enable the www.advancedsciencenews.com www.adpr-journal.com detection of different VOCs, achieving limits of detection of 0.01 vol% at room temperature, overperforming the results of nonfractal planar geometry. [23][24][25] Similarly, when applied as a catalyst for electrochemical CO 2 reduction reactions, Au-Bi 2 O 3 fractal structures show high selectivity to formate (HCOO À ) achieving high faradaic efficiency of 97% and high mass-specific formate current density of À54 mA mg À1 at À1.1 V versus a reversible hydrogen electrode (RHE), which is %3 times better than that of a control nonfractal Bi 2 O 3 catalyst.…”

Section: Resultsmentioning

confidence: 99%

“…In fact, in addition to the elevated near-field due to the LSPR excitation, fractal systems can further localize the electromagnetic radiation in subwavelengths volumes due to a great enhancement of the scattering cross section. [17,18] Pioneering works on this effect include the numerical and experimental study by Tsai et al [17] on silver colloidal fractal structures. Using photon scanning tunneling microscopy (PSTM), they have directly imaged the localization of dipolar eigenmodes due to the localized surface plasmons and they have shown a high sensitivity of these modes to frequency and polarization.…”

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confidence: 99%

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Engineering Fractal Photonic Metamaterials by Stochastic Self‐Assembly of Nanoparticles

Fusco

Trần‐Phú

Cembran

et al. 2021

Advanced Photonics Research

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In nanophotonics, precise arrangements of the nanostructures, periodicity, and spatial order are key design principles for the realization of metamaterials, featuring properties that are not found in naturally occurring systems. [1] In the past decade, understanding the optical response of two-dimensionally distributed nanomaterials has led to significant advance in flat optics, providing new ways to model, design, and develop integrated photonic chips, photonic crystals, negative refraction metamaterials, perfect lenses, and topological materials, to name a few examples. [2] More recently, introduction of controlled degrees of irregularities in photonic metamaterials is being explored to add further functionalities extending the range of applications. [3,4] Pioneering works on aperiodic nanostructures started by replicating the complexity and self-similarity of natural systems such as beetles, butterflies, and leaves, to extrapolate and understand the hidden secrets of their randomness and to achieve, for instance, structural coloring, energy harvesting, and innovative biochemical sensors. [5] Nature provides plenty examples of, at first sight, irregular and disordered structures that, however, follow self-similar patterns, such as snowflakes, lightning bolts, heartbeat, and pulmonary vessels. [6] These systems fall in the category of random fractals, defined as complex objects that show a statistical recursive pattern at different scales. [7] The degree of complexity of a fractal system is commonly defined by the fractal

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Engineering Fractal Photonic Metamaterials by Stochastic Self‐Assembly of Nanoparticles

Fusco

Trần‐Phú

Cembran

et al. 2021

Advanced Photonics Research

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“…[18][19][20][21][22][23][24] The nature of localization of electromagnetic modes in fractal aggregates have been a subject of intensive study. 16,[25][26][27][28][29][30] Optical properties of fractal soot are of significant importance in atmospheric optics and climate research. [31][32][33][34] Another topic of recent interest is femtosecond dynamics of local excitations in fractal aggregates.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic density of states and absorption of radiation by aggregates of nanospheres with multipole interactions

et al. 2004

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We calculate the quasistatic electromagnetic density of states for aggregates of touching spheres, in particular, linear chains and computer-generated random fractal aggregates. Multipole moments with orders of up to L = 64 are taken into account for random aggregates with the number of particles of up to N = 100 and up to L = 8000 for linear chains. Extensive comparisons with the dipole approximation and geometrical cluster renormalization method are performed. Extinction spectra are calculated for several metals and black carbon. Long wavelength electromagnetic properties of fractal aggregates are considered in details.

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“…Therefore a model of diluted aggregates was adopted and used, for example, in Refs. [8,21,22,31,32,33,34]. According to this model, an aggregate of N touching spheres (where N can be very large) is diluted, i.e., spheres were randomly removed from the aggregate with the probability 1 − p, where p ≪ 1.…”

Section: Introductionmentioning

confidence: 99%

Local anisotropy and giant enhancement of local electromagnetic fields in fractal aggregates of metal nanoparticles

Карпов

Gerasimov²,

Isaev³

et al. 2005

Phys. Rev. B

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We have shown within the quasistatic approximation that the giant fluctuations of local electromagnetic field in random fractal aggregates of silver nanospheres are strongly correlated with a local anisotropy factor S which is defined in this paper. The latter is a purely geometrical parameter which characterizes the deviation of local environment of a given nanosphere in an aggregate from spherical symmetry. Therefore, it is possible to predict the sites with anomalously large local fields in an aggregate without explicitly solving the electromagnetic problem. We have also demonstrated that the average (over nanospheres) value of S does not depend noticeably on the fractal dimension D, except when D approaches the trivial limit D = 3. In this case, as one can expect, the average local environment becomes spherically symmetrical and S approaches zero. This corresponds to the well-known fact that in trivial aggregates fluctuations of local electromagnetic fields are much weaker than in fractal aggregates. Thus, we find that, within the quasistatics, the large-scale geometry does not have a significant impact on local electromagnetic responses in nanoaggregates in a wide range of fractal dimensions. However, this prediction is expected to be not correct in aggregates which are sufficiently large for the intermediate-and radiation-zone interaction of individual nanospheres to become important.

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Scattering and localization of light on fractals

Cited by 22 publications

References 8 publications

Engineering Fractal Photonic Metamaterials by Stochastic Self‐Assembly of Nanoparticles

Engineering Fractal Photonic Metamaterials by Stochastic Self‐Assembly of Nanoparticles

Electromagnetic density of states and absorption of radiation by aggregates of nanospheres with multipole interactions

Local anisotropy and giant enhancement of local electromagnetic fields in fractal aggregates of metal nanoparticles

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