Cross section of light absorption and light scattering for noble metal (silver, gold) nanoparticle is higher than its geometrical cross section in case of plasmon resonance. It can be comparatively easy recognized from, for example, Mie theoretical calculations, for example, here:
https://saviot.cnrs.fr/mie/index.en.html
Vertical axis on that web-page shows how much times light absorption (or scattering) cross section is bigger than geometrical cross section of nanoparticle at different wavelengths of light.
It means that in resonance case incident light will be absorbed both by nanoparticle and by the neighborhood points, which are 10-20 nm distant from the nanoparticle surface. However, plasmonic electric field is not very intensive at such distances from nanoparticle surface, because it is maximal on the nanoparticle surface and decays exponentially outside. Then is it correct to say that increase in absorption and scattering cross sections is caused by localized plasmonic electric field? I mean that it looks so that this field is not very intensive at the edges of these cross sections.
You are true that it is caused by localized surface plasmon resonance.
Yes, plasmonic near field can induce localized surface plasmon resonance.
Absorption cross-section is indeed measured in cm2, so it designates an area. But I suggest to think of it as the area which, if hit by the photon, will trigger photon absorption. And this photon is absorbed by the particle only, not by particle plus neighbourhood. So a resonant particle will absorb a photon easier / with higher efficiency, the probability of absorption being higher when absorption cross-section is higher. Then, I would not say that the increase of absorption cross section is caused by plasmonic electric fields, but I would say that it is caused by the fact that photons have the possibility to excite/create plasmons in the particle.
- Badges
- Science topic
- Similar topics
- Biological Science
- Histology
- Sectioning