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The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

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ABSTRACT

This paper presents a theoretical study of the interaction of a 6 ps laser pulse with uncoupled and plasmon-coupled gold nanoparticles. We show how the one-dimensional assembly of particles affects the optical breakdown threshold of its surroundings. For this purpose we used a fully coupled electromagnetic, thermodynamic and plasma dynamics model for a laser pulse interaction with gold nanospheres, nanorods and assemblies, which was solved using the finite element method. The thresholds of optical breakdown for off- and on-resonance irradiated gold nanosphere monomers were compared against nanosphere dimers, trimers, and gold nanorods with the same overall size and aspect ratio. The optical breakdown thresholds had a stronger dependence on the optical near-field enhancement than on the mass or absorption cross-section of the nanostructure. These findings can be used to advance the nanoparticle-based nanoscale manipulation of matter.

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Related in: MedlinePlus

The optical breakdown threshold, Fth, which is required to reach the critical electron density, ρcr = 1020 (cm−3), is plotted against (a) the nanoparticle volume, Vnp, (b) the absorption cross section, σabs, and (c) the maximum near-field enhancement, /E/max/E0. Symbols and color scheme are the same as in Fig. 6 at ρe = 1020 cm−3.
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Figure 7: The optical breakdown threshold, Fth, which is required to reach the critical electron density, ρcr = 1020 (cm−3), is plotted against (a) the nanoparticle volume, Vnp, (b) the absorption cross section, σabs, and (c) the maximum near-field enhancement, /E/max/E0. Symbols and color scheme are the same as in Fig. 6 at ρe = 1020 cm−3.

Mentions: Fig. 7 plots the threshold Fth as a function of Vnp, σabs, /E/max/E0. Nanoparticles of different morphology but with comparable volumes need different fluences to reach optical breakdown threshold, which can be seen by comparing r15t@800 against s25m@532; s15t@585, r15d@660 and s15t@532 against each other; and r5d@660 s5t@560 and s5t@532 against each other. On the other hand, an on-resonance irradiated s25t@640 and r25d@720 with comparable absorption cross-sections had Fth = 0.37 mJ/cm3 and Fth = 1.4 mJ/cm3, respectively. A similar situation can be seen comparing s25d@595 against r15d@660, and s15t@585, s25d@532 and s25t@532 against each other, where the nanoparticles with different morphology but comparable absorption cross-section have different optical breakdown thresholds. A power regression fit of the optical breakdown threshold versus the volume of the nanoparticle yielded, Fth = 2.5969Vnp−0.26 with R2 = 0.32, and a power regression fit of the optical breakdown threshold versus the absorption cross-section yield, Fth = 0.8363σabs−0.311 with R2 = 0.46. Fig. 7 shows the relation between the maximum field enhancement for different morphologies, wavelengths of laser irradiation and optical breakdown threshold. A power regression fit of the optical breakdown versus the maximum field enhancement yielded, Fth = 44.96(/E/max/E0)−1.267 with R2 = 0.92. The strong dependence of the optical breakdown threshold on the near-field enhancement compared to the poor dependence on morphology and absorption cross-section is important knowledge for the design of appropriate nanostructures for lowering the optical breakdown threshold.


The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures
The optical breakdown threshold, Fth, which is required to reach the critical electron density, ρcr = 1020 (cm−3), is plotted against (a) the nanoparticle volume, Vnp, (b) the absorption cross section, σabs, and (c) the maximum near-field enhancement, /E/max/E0. Symbols and color scheme are the same as in Fig. 6 at ρe = 1020 cm−3.
© Copyright Policy - Beilstein
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4979631&req=5

Figure 7: The optical breakdown threshold, Fth, which is required to reach the critical electron density, ρcr = 1020 (cm−3), is plotted against (a) the nanoparticle volume, Vnp, (b) the absorption cross section, σabs, and (c) the maximum near-field enhancement, /E/max/E0. Symbols and color scheme are the same as in Fig. 6 at ρe = 1020 cm−3.
Mentions: Fig. 7 plots the threshold Fth as a function of Vnp, σabs, /E/max/E0. Nanoparticles of different morphology but with comparable volumes need different fluences to reach optical breakdown threshold, which can be seen by comparing r15t@800 against s25m@532; s15t@585, r15d@660 and s15t@532 against each other; and r5d@660 s5t@560 and s5t@532 against each other. On the other hand, an on-resonance irradiated s25t@640 and r25d@720 with comparable absorption cross-sections had Fth = 0.37 mJ/cm3 and Fth = 1.4 mJ/cm3, respectively. A similar situation can be seen comparing s25d@595 against r15d@660, and s15t@585, s25d@532 and s25t@532 against each other, where the nanoparticles with different morphology but comparable absorption cross-section have different optical breakdown thresholds. A power regression fit of the optical breakdown threshold versus the volume of the nanoparticle yielded, Fth = 2.5969Vnp−0.26 with R2 = 0.32, and a power regression fit of the optical breakdown threshold versus the absorption cross-section yield, Fth = 0.8363σabs−0.311 with R2 = 0.46. Fig. 7 shows the relation between the maximum field enhancement for different morphologies, wavelengths of laser irradiation and optical breakdown threshold. A power regression fit of the optical breakdown versus the maximum field enhancement yielded, Fth = 44.96(/E/max/E0)−1.267 with R2 = 0.92. The strong dependence of the optical breakdown threshold on the near-field enhancement compared to the poor dependence on morphology and absorption cross-section is important knowledge for the design of appropriate nanostructures for lowering the optical breakdown threshold.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

This paper presents a theoretical study of the interaction of a 6 ps laser pulse with uncoupled and plasmon-coupled gold nanoparticles. We show how the one-dimensional assembly of particles affects the optical breakdown threshold of its surroundings. For this purpose we used a fully coupled electromagnetic, thermodynamic and plasma dynamics model for a laser pulse interaction with gold nanospheres, nanorods and assemblies, which was solved using the finite element method. The thresholds of optical breakdown for off- and on-resonance irradiated gold nanosphere monomers were compared against nanosphere dimers, trimers, and gold nanorods with the same overall size and aspect ratio. The optical breakdown thresholds had a stronger dependence on the optical near-field enhancement than on the mass or absorption cross-section of the nanostructure. These findings can be used to advance the nanoparticle-based nanoscale manipulation of matter.

No MeSH data available.


Related in: MedlinePlus