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Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell during initial stage of shell expansion.

Pustovalov VK, Astafyeva LG - Nanoscale Res Lett (2011)

Bottom Line: Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated.Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values.The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion.PACS: 42.62.BE. 78.67.

View Article: PubMed Central - HTML - PubMed

Affiliation: Belarusian National Technical University, Independence pr, 65, Minsk, 220013, Belarus. pustovalovv@mail.ru.

ABSTRACT
Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated. Vapor shell expansion leads to decreasing up to one to two orders of magnitude in comparison with initial values of scattering and extinction of the radiation with wavelengths 532 and 633 nm by system while shell radius is increased up to value of about two radii of nanoparticle. Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values. The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion.PACS: 42.62.BE. 78.67. BF.

No MeSH data available.


Angular distributions (optical indicatrixes) of radiation intensity Isca. With wavelength 532 nm (a), 633 nm (b), and 780 (c) nm scattered by two-layered spherical system gold NP core and water vapor shell placed in water for the NP radius r0 = 20 nm and radii of system r1 = r0 (1, pure gold NP, straight line), r1 = r0 + 0.1r0 (2, dotted line), r1 = r0 + 1r0 (3, straight line), r1 = r0 + 2r0 (4, dashed-dotted line), r1 = r0 + 3r0 (5, straight line), r1 = r0 + 4r0 (6, straight line). Direction of laser radiation propagation is from left to right (from 180° to 0°). Polar coordinates show angles for scattered radiation in the range 0° to 360°; scale Isca shows arbitrary units of intensity.
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Figure 4: Angular distributions (optical indicatrixes) of radiation intensity Isca. With wavelength 532 nm (a), 633 nm (b), and 780 (c) nm scattered by two-layered spherical system gold NP core and water vapor shell placed in water for the NP radius r0 = 20 nm and radii of system r1 = r0 (1, pure gold NP, straight line), r1 = r0 + 0.1r0 (2, dotted line), r1 = r0 + 1r0 (3, straight line), r1 = r0 + 2r0 (4, dashed-dotted line), r1 = r0 + 3r0 (5, straight line), r1 = r0 + 4r0 (6, straight line). Direction of laser radiation propagation is from left to right (from 180° to 0°). Polar coordinates show angles for scattered radiation in the range 0° to 360°; scale Isca shows arbitrary units of intensity.

Mentions: Figure 4 presents angular distributions (optical indicatrixes) of radiation intensity Isca with wavelengths λ = 532, 633, and 780 nm scattered by two-layered spherical system gold NP core and water vapor shell for the NP radius r0 = 20 nm and different radii of system r1. The increase of vapor shell thickness till Δr1 ≤ r0 for λ = 532, 633, and 780 nm leads to decrease of scattered radiation intensity in approximately 50 ÷ 300 times in all scattered directions. Only at Δr1 ≈ 2r0 scattering intensity is approximately equal initial distribution of scattered radiation from pure NP. Then, further growth of vapor shell thickness tends to essential increase of scattered radiation intensity (in 20 ÷ 100 times for Δr1 = 4r0) in comparison to the case of pure Au NP. This fact is well correlated with the behavior of σsca (Figures 1 and 2). With growth of Δr1, optical indicatrixes become essentially extended in the forward direction (angle 0°). We have to note that mathematical modeling of optical indicatrixes of scattered radiation was independently carried out on the base of optical constants without use of calculated values of σsca. This behavior of indicatrixes of scattered radiation is additional evidence of nonlinear (decreasing and increasing) properties of system NP core and vapor shell during initial stages of bubble expansion till r1 ≤ 2r0.


Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell during initial stage of shell expansion.

Pustovalov VK, Astafyeva LG - Nanoscale Res Lett (2011)

Angular distributions (optical indicatrixes) of radiation intensity Isca. With wavelength 532 nm (a), 633 nm (b), and 780 (c) nm scattered by two-layered spherical system gold NP core and water vapor shell placed in water for the NP radius r0 = 20 nm and radii of system r1 = r0 (1, pure gold NP, straight line), r1 = r0 + 0.1r0 (2, dotted line), r1 = r0 + 1r0 (3, straight line), r1 = r0 + 2r0 (4, dashed-dotted line), r1 = r0 + 3r0 (5, straight line), r1 = r0 + 4r0 (6, straight line). Direction of laser radiation propagation is from left to right (from 180° to 0°). Polar coordinates show angles for scattered radiation in the range 0° to 360°; scale Isca shows arbitrary units of intensity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211867&req=5

Figure 4: Angular distributions (optical indicatrixes) of radiation intensity Isca. With wavelength 532 nm (a), 633 nm (b), and 780 (c) nm scattered by two-layered spherical system gold NP core and water vapor shell placed in water for the NP radius r0 = 20 nm and radii of system r1 = r0 (1, pure gold NP, straight line), r1 = r0 + 0.1r0 (2, dotted line), r1 = r0 + 1r0 (3, straight line), r1 = r0 + 2r0 (4, dashed-dotted line), r1 = r0 + 3r0 (5, straight line), r1 = r0 + 4r0 (6, straight line). Direction of laser radiation propagation is from left to right (from 180° to 0°). Polar coordinates show angles for scattered radiation in the range 0° to 360°; scale Isca shows arbitrary units of intensity.
Mentions: Figure 4 presents angular distributions (optical indicatrixes) of radiation intensity Isca with wavelengths λ = 532, 633, and 780 nm scattered by two-layered spherical system gold NP core and water vapor shell for the NP radius r0 = 20 nm and different radii of system r1. The increase of vapor shell thickness till Δr1 ≤ r0 for λ = 532, 633, and 780 nm leads to decrease of scattered radiation intensity in approximately 50 ÷ 300 times in all scattered directions. Only at Δr1 ≈ 2r0 scattering intensity is approximately equal initial distribution of scattered radiation from pure NP. Then, further growth of vapor shell thickness tends to essential increase of scattered radiation intensity (in 20 ÷ 100 times for Δr1 = 4r0) in comparison to the case of pure Au NP. This fact is well correlated with the behavior of σsca (Figures 1 and 2). With growth of Δr1, optical indicatrixes become essentially extended in the forward direction (angle 0°). We have to note that mathematical modeling of optical indicatrixes of scattered radiation was independently carried out on the base of optical constants without use of calculated values of σsca. This behavior of indicatrixes of scattered radiation is additional evidence of nonlinear (decreasing and increasing) properties of system NP core and vapor shell during initial stages of bubble expansion till r1 ≤ 2r0.

Bottom Line: Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated.Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values.The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion.PACS: 42.62.BE. 78.67.

View Article: PubMed Central - HTML - PubMed

Affiliation: Belarusian National Technical University, Independence pr, 65, Minsk, 220013, Belarus. pustovalovv@mail.ru.

ABSTRACT
Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated. Vapor shell expansion leads to decreasing up to one to two orders of magnitude in comparison with initial values of scattering and extinction of the radiation with wavelengths 532 and 633 nm by system while shell radius is increased up to value of about two radii of nanoparticle. Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values. The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion.PACS: 42.62.BE. 78.67. BF.

No MeSH data available.