Paradoxes in laser heating of plasmonic nanoparticles

Abstract

We study the problem of the laser heating of plasmonic nanoparticles and demonstrate that, in sharp contrast to the common belief, a particle with a small dissipative constant absorbs much more energy than the particle with a large value of this constant. Even higher effective absorption may be achieved for core-shell nanoparticles. Our analysis uses the exact Mie solutions, and optimization of the input energy is performed at a fixed fluence with respect to the particle size, wavelength and duration of the laser pulse. We introduce a new quantity, the effective absorption coefficient of a particle, which allows one to compare quantitatively the light absorption by nanoparticles with that of a bulk material. We describe a range of parameters where a giant absorption enhancement can be observed and give practical examples of metals whose optical properties vary from weak (potassium) to strong (platinum) dissipation. Show more