Characteristics of Laser-Induced Plasma in Porous Anodic Aluminum Oxide

Taking anodic aluminum oxide (AAO) with different pore diameters as research object,we study the effects of pore size of AAO on the morphological evolution and temperature of laser-induced plasma based on high-speed photography and atomic emission spectroscopy. The light reflectance of samples is tested and simulated by absorption spectroscopy and finite-difference time-domain (FDTD) method.The results show that within a certain pore range, as the AAO pore size decreases, plasma duration becomes long, the spectral line intensity becomes large, and the plasma electron temperature becomes high. The plasma parameters of AAO are larger than those of polished aluminum sheet, in which electron temperature of plasma of AAO is 2000-3500 K higher than that of polished aluminum sheet. Within a certain pore range, the smaller the AAO pore, the higher absorption coefficient of light in the sample, which explains the reason of AAO plasma enhancement. © 2019, Chinese Lasers Press. All right reserved.