Plasmon-Assisted Optofluidics

Abstract

We study the ability of a plasmonic structure under illumination to release heat and induce fluid convection at the nanoscale. We first introduce the unified formalism associated with this multidisciplinary problem combining optics, thermodynamics, and hydrodynamics. On this basis, numerical simulations were performed to compute the temperature field and velocity field evolutions of the surrounding fluid for a gold disk on glass while illuminated at its plasmon resonance. We show that the velocity amplitude of the surrounding fluid has a linear dependence on the structure temperature and a quadratic dependence on the structure size (for a given temperature). The fluid velocity remains negligible for single nanometer-sized plasmonic structures (<1 nm/s) due to a very low Reynolds number. However thermal-induced fluid convection can play a significant role when considering either micrometer-size structures or an assembly of nanostructures.

Steam generation in a nanoparticle-based solar receiver

“…Similar to the concept of energy localization on the surface [18], it appears that solar energy was localized by the nanoparticles. It was further hypothesized that rapid heating of nanoparticles produced nanobubbles immediately around the nanoparticles, and the rise of nanobubbles to the top surface of the liquid realized the release of the vapor produced [19][20][21]. Subsequent simulation work [11,16,17,22] showed the possibility of nanobubble formation based on a non-equilibrium phase change assumption.…”

Characterization of the near-field and convectional transport behavior of micro and nanoparticles in nanoscale plasmonic optical lattices

“…The numerical simulations indicated a small temperature increase (a maximum of $3 K) when using an experimentally determined adsorption coefficient, 37 which cannot explain neither this difference nor the velocity difference between the nanoplasmonic array with ITO and the ITO layer only, as seen in Figure 4. 29 Differences between the current work and a previous work by Toussaint's group 23 include identification of a different mechanism for the high fluidic velocity of out-of-lattice transport, which was determined here, by carefully comparing photothermal convection from simulation. Essentially, we obtained a maximal velocity $0.8 lm/s at the location z ¼ 80 lm above the center of the lattice, 29 which is of the same order of magnitude as Toussaint's results.…”

“…Quidant's group used a Green's function approach to calculate both the temperatures of plasmonic nanostructures of various shapes, including nanospheres and nanodiscs, 21,22 and fluidic convection velocities, on the order of $nm/s, near single isolated plasmonic nanostructures. 23 Using the same approach, Baffou et al showed that the temperature profile of a plasmonic nanodisc array could be calculated by summing over the contributions of each individual nanodisc; these calculations were validated experimentally. 24 Toussaint's group calculated the convection flow induced by an array of nanoantennas, and concluded that the optically absorptive, thermally conductive indium tin oxide (ITO) could efficiently distribute the thermal energy to generate an increase in convection velocity.…”

Optofluidics incorporating actively controlled micro- and nano-particles

“…II C. 189,190 Sources of heat can be optical, mechanical, or electrical. It has also been demonstrated that certain plasmonic nanostructures 191 and thermally responsive particle composites 192 absorb and induce localized heating upon exposure to light. Duhr and Braun 193 demonstrated the thermophoretic transport of DNA molecules.…”