摘要： Controlling the formation of nanoparticles (NPs) by direct laser writing ensures an efficient way of engineering the optical responses of nanocomposite materials through adjusting laser parameters such as power, focusing and writing speed. The process of NP’s growth, photo-oxidation, and reduction affect the light absorption by an ensemble of laser-activated NPs. However, those self-consistent processes are not well understood. Previous studies explained the growth or shrinkage of silver NPs by neglecting heat diffusion. It remained unclear, however, how the NP size can be controlled by the laser writing speed. In this work, based on the coupled calculations of size-variation, light absorption, and heat diffusion by an emsemble of NPs, we propose a two-dimensional model taking account of spatial information of size and temperature to have a further investigation into the process. The spatial size distribution is revealed to be non-uniform leading to the transmission inhomogeneity along the laser written lines. This fact is confirmed by the in-situ transmission experiments. The performed study also depicts a novel view in which NPs grow ahead of the laser beam center due to the heat diffusion. The nonlinear growth never stops until it exhausts the majority of the free Ag0 in the matrix, while the amount of Ag0 by reduction cannot compensates the consumption. After that, the photo-oxidation dominates the process and finally acts as the controlling role in NP size depending on the writing speed. The simulations also show that it is not the activation energy of Ag0 diffusion but the ionization efficiency affect the final NP size, which helps understand in how to improve the laser processing of differently prepared samples.