The σabs of laser shining on a 30 nm diameter Au nanoparticle decorated on a TiO2 powder film can be estimated using Mie theory with a refractive index (RI) of ~2.60 and 1.0003 for TiO2 and air, respectively. The value of σabs (~1280 nm 2 ) for the 532 nm laser is much higher than that (60 nm 2 ) for the 638 nm laser as the resonance of the Au NPs is at 533 nm. The value of thermal conductivity ( 𝜅̅ ) is taken as