Manipulation of temperature dependence of photothermal response in metal nanoparticles by wavelength detuning

We investigate the temperature dependence of the absorption cross-section of an ideal Drude like metal, Au and Ag nanoparticles. We show that when Au or Ag nanoparticles held on a SiO$_{2}$ substrate are irradiated at the resonance wavelength (at the reference temperature), model predictions for the steady-state temperature can differ substantially from that obtained by treating the absorption cross-section to be temperature independent. Red-shifting of the laser wavelength from the resonance can lead to a monotonic increase in absorption cross-section with near linear increase in the temperature. Potential applications of such photothermal behavior will be discussed.