Peculiarities of light absorption by spherical microcapsules

Yurii E. Geints; Ekaterina K. Panina; Alexander A. Zemlyanov

doi:10.1117/12.2300750

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16 April 2018 Peculiarities of light absorption by spherical microcapsules

Yurii E. Geints, Ekaterina K. Panina, Alexander A. Zemlyanov

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Proceedings Volume 10614, International Conference on Atomic and Molecular Pulsed Lasers XIII; 106141B (2018) https://doi.org/10.1117/12.2300750
Event: XIII International Conference on Atomic and Molecular Pulsed Lasers, 2017, Tomsk, Russia

Abstract

Optical radiation absorption in the poly-layer spherical microparticles simulating the inorganic/organic polyshell absorbing microcapsules is considered. With the aim of the finite-difference time-domain technique, the spatial distribution of the absorbed light power in microcapsules of various sizes and internal structure is numerically calculated. For the purpose of light absorption enhancement, we have engineered the optimal structure of a capsule consisting of a strong-refracting transparent outer coating and an absorbing layer which covers a liquid core. The proposed microcapsule prototype provides for a manifold increase in the absorbed light power density in comparison with the usual single-layer absorbing capsule. We show that for light-wavelengths-scaled microcapsules it is optimal to use a material with the refractive index larger than two as an outer shell, for example, titanium dioxide (TiO₂). The highest values of the absorbed power density can be obtained in microcapsules with absorbing shell thickness of approximately a tenth of a laser wavelength. When laser radiation is scattered by a dimer constituted by two identical absorbing microcapsules the absorbed power density can be maximized by the choosing of proper dimer spatial configuration. In the case of strongly absorbing particles, the absorption maximum corresponds to a shift of the capsules to a distance of about their diameter, and in the case of weakly absorbing particles the absorption is maximal when particles are in geometrical shades of each other.

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Yurii E. Geints, Ekaterina K. Panina, and Alexander A. Zemlyanov "Peculiarities of light absorption by spherical microcapsules", Proc. SPIE 10614, International Conference on Atomic and Molecular Pulsed Lasers XIII, 106141B (16 April 2018); https://doi.org/10.1117/12.2300750

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