Department of Physics, Faculty of Basic Sciences, Shahed University, Tehran, Iran
Nanomaterials group, Department of Materials Engineering, Tarbiat Modares University, Tehran, P.O. Box: 14115-143, Iran
In this research the heating process and melting of water surrounded homogenous gold nanospheres irradiated by nanosecond laser pulses at the wavelengths of 355, 532, 633, and 900 nm are studied. The estimation of absorbed energy by gold nanoparticles with radius range 1-40 nm and their maximum temperature is calculated using the absorption efficiency of the nanoparticles at corresponding laser wavelength. The dependency of the melting temperature of nanoparticles upon their size is also considered. It is seen that the progress in the melting process strongly depend on the laser wavelength and particle size. The laser wavelength of 532 nm has been found appropriate for effective photothermal heating of a large gold nanoparticle. Controlling the laser irradiation wavelength is crucial to achieve the best conditions for the desired applications such as localized heating and nanowelding.