I'm trying to better understand what exactly happens when a laser beam hits a surface (apart from reflection). Say I have a thick gold surface (could be coated with gold nanoparticles if that helps) and I point a 50 mW CW red laser onto that surface:
My understanding is that the photons excite plasmon modes and that the plasmon modes can decay by exciting phonon modes -- since all three are somewhat coupled. In the end, all absorbed energy ends up in phonon modes (per this discussion).
My questions: First of all, is this picture correct? And second, what aspects of this can be measured experimentally? E.g. can I measure the extent to which my laser excites plasmon modes and/or phonon modes?