Thermoplasmonic-Induced Superheating, Microbubble and Fluid Convection in Liquid Media

In this presentation, focus will be put on the physics of microscale thermo-induced processes in liquids assisted by plasmonic heating. First, we will explain why superheating can be easily achieved in plasmonics, and detail the main consequences and possible applications of such a phenomenon. Then, We will focus on plasmonic microbubble generation under cw illumination and explain the origin of their unexpected nature and dynamics. Finally, we will focus on plasmon-induced fluid convection to answer the question "how fast can a fluid be moved on the microscale using nanoplasmonics means". In particular, we will show that microscale fluid convection can be strongly enhanced by the two aforementioned processes: superheating and bubble generation. All the experimental works presented herein have been made it possible using our recently developed thermal microscopy technique based on optical wavefront sensing.

Figure: (a) SEM image of gold nanospheres made by block copolymer lithography. (b,c) Heat source density and temperature maps, quantitatively measured using optical wavefront sensing. (d) Radial fluid velocity around gold nanoparticle under superheating. (e) Bright field image of latex beads trajectories rendering fluid velocity around a single gold nanoparticle. (f) Laser induced inner boiling inside a plasmonic microbubble.

References:

[1] Super-heating and micro-bubble generation around plasmonic nanoparticles under cw illumination
Baffou et al., Journal Physical Chemisty C 118, 4890 (2014)

[2] Photo-induced heating of nanoparticle arrays
Baffou et al., ACS Nano 7, 6478–6488 (2013)

[3] Thermo-plasmonics: using metallic nanostructures as nano-sources of heat
Baffou, Quidant, Laser and Photonics Reviews 7, 171-187 (2013)

[4] Thermal imaging of nanostructures by quantitative optical phase analysis
Baffou et al., ACS Nano 6, 2452–2458 (2012)

guillaume.baffou@fresnel.fr