### Abstract

There are two widely accepted restrictions on the application of the discrete dipole approximation (DDA) in the study of light scattering by particles comparable to the wavelength: (1) when considering dielectric particles, the size of the cells must satisfy the condition kκd\m\ > 0.5, where k is the wave number, d is the size of the cells, and m is the complex refractive index of the constituent material and (2) when considering conductive particles, the size of the cells must be small enough to reproduce sufficiently the evolution of the electromagnetic field in the skin layer. We examine both restrictions when the DDA is applied to irregularly shaped particles and show that its restrictions are not as strong as is widely accepted. For instance, when studying irregularly shaped particles averaged over orientations, even at kd\m\ = 1, the DDA provides highly accurate numerical results. Moreover, we show that the impact of using large constituent cells is similar to that produced by surface roughness; therefore, the replacement of the target particle by an array of large constituent cells has the same effect, qualitatively, as incorporating additional small-scale surface roughness on the particle. Such a modification of the target particle can be desirable in many practical applications of DDA when irregularly shaped particles are considered. When applying DDA to conductive, nonspherical particles, the insufficient description of the electromagnetic field in the skin layer does not lead to a violation ofthe Maxwell equations, although it has a visible but nonmajor influence on the light-scattering properties of the target.

Original language | English |
---|---|

Pages (from-to) | 1267-1279 |

Number of pages | 13 |

Journal | Applied Optics |

Volume | 49 |

Issue number | 8 |

DOIs | |

Publication status | Published - Mar 10 2010 |

Externally published | Yes |

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### All Science Journal Classification (ASJC) codes

- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering

### Cite this

*Applied Optics*,

*49*(8), 1267-1279. https://doi.org/10.1364/AO.49.001267

**Validity criteria of the discrete dipole approximation.** / Zubko, Evgenij; Petrov, Dmitry; Grynko, Yevgen; Shkuratov, Yuriy; Okamoto, Hajime; Muinonen, Karri; Nousiainen, Timo; Kimura, Hiroshi; Yamamoto, Tetsuo; Videen, Gorden.

Research output: Contribution to journal › Article

*Applied Optics*, vol. 49, no. 8, pp. 1267-1279. https://doi.org/10.1364/AO.49.001267

}

TY - JOUR

T1 - Validity criteria of the discrete dipole approximation

AU - Zubko, Evgenij

AU - Petrov, Dmitry

AU - Grynko, Yevgen

AU - Shkuratov, Yuriy

AU - Okamoto, Hajime

AU - Muinonen, Karri

AU - Nousiainen, Timo

AU - Kimura, Hiroshi

AU - Yamamoto, Tetsuo

AU - Videen, Gorden

PY - 2010/3/10

Y1 - 2010/3/10

N2 - There are two widely accepted restrictions on the application of the discrete dipole approximation (DDA) in the study of light scattering by particles comparable to the wavelength: (1) when considering dielectric particles, the size of the cells must satisfy the condition kκd\m\ > 0.5, where k is the wave number, d is the size of the cells, and m is the complex refractive index of the constituent material and (2) when considering conductive particles, the size of the cells must be small enough to reproduce sufficiently the evolution of the electromagnetic field in the skin layer. We examine both restrictions when the DDA is applied to irregularly shaped particles and show that its restrictions are not as strong as is widely accepted. For instance, when studying irregularly shaped particles averaged over orientations, even at kd\m\ = 1, the DDA provides highly accurate numerical results. Moreover, we show that the impact of using large constituent cells is similar to that produced by surface roughness; therefore, the replacement of the target particle by an array of large constituent cells has the same effect, qualitatively, as incorporating additional small-scale surface roughness on the particle. Such a modification of the target particle can be desirable in many practical applications of DDA when irregularly shaped particles are considered. When applying DDA to conductive, nonspherical particles, the insufficient description of the electromagnetic field in the skin layer does not lead to a violation ofthe Maxwell equations, although it has a visible but nonmajor influence on the light-scattering properties of the target.

AB - There are two widely accepted restrictions on the application of the discrete dipole approximation (DDA) in the study of light scattering by particles comparable to the wavelength: (1) when considering dielectric particles, the size of the cells must satisfy the condition kκd\m\ > 0.5, where k is the wave number, d is the size of the cells, and m is the complex refractive index of the constituent material and (2) when considering conductive particles, the size of the cells must be small enough to reproduce sufficiently the evolution of the electromagnetic field in the skin layer. We examine both restrictions when the DDA is applied to irregularly shaped particles and show that its restrictions are not as strong as is widely accepted. For instance, when studying irregularly shaped particles averaged over orientations, even at kd\m\ = 1, the DDA provides highly accurate numerical results. Moreover, we show that the impact of using large constituent cells is similar to that produced by surface roughness; therefore, the replacement of the target particle by an array of large constituent cells has the same effect, qualitatively, as incorporating additional small-scale surface roughness on the particle. Such a modification of the target particle can be desirable in many practical applications of DDA when irregularly shaped particles are considered. When applying DDA to conductive, nonspherical particles, the insufficient description of the electromagnetic field in the skin layer does not lead to a violation ofthe Maxwell equations, although it has a visible but nonmajor influence on the light-scattering properties of the target.

UR - http://www.scopus.com/inward/record.url?scp=77949777560&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77949777560&partnerID=8YFLogxK

U2 - 10.1364/AO.49.001267

DO - 10.1364/AO.49.001267

M3 - Article

C2 - 20220882

AN - SCOPUS:77949777560

VL - 49

SP - 1267

EP - 1279

JO - Applied Optics

JF - Applied Optics

SN - 1559-128X

IS - 8

ER -