“…37 Under laser irradiation, the heat of nanospheres is transferred to the surrounding medium. In the previous works, based on a TTM, the simulations of thermal problems excited using picosecond and nanosecond pulse lasers have been reported, such as the thermal conversion and morphology change of gold nanorods excited with a 7 ns pulse laser, 38 the thermal diffusion during laser-induced ablation of metals (25 ns), 39 and the energy deposition processes initiated by 30 ps laser excitation, 40 etc. Therefore, when t w lies within the range from 10 ps to 10 ns, the temperature T can be calculated using a TTM: 41 ![]()
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where c e , c l and c w are the heat capacity per unit volume of the gold electron, the heat capacity per unit volume of the gold lattice, and the heat capacity per unit mass of water, respectively, κ is the thermal conductivity, g is the electron–lattice coupled coefficient, t is time, ρ is density, and S ( t ) is the heat source density, which can be calculated using the following equation: 21 S ( t ) = C abs · I ( t )/ V p where V p is the volume of gold nanospheres and I is the power density of the Gaussian pulse laser: 21
where F is the laser flux, t 0 is the peak time of the laser power,
is the standard deviation of the Gaussian function, and t w is the pulse duration.…”