Preparation Of AAO Films By Two-step Anodization And Their Laser Irradiation Properties

Metal/nonmetal functional materials with high optical absorptivity surface have important potential applications in the field of optical and photoelectron.Porous material belongs to a typical super high optical absorption coefficient material.In this paper,AAO film was prepared by two-step anodization and chosen as the research object,the influence of different preparation conditions on the morphology and size of AAO films was studied.Plasma characteristics of AAO thin films were investigated by transient plasma emission spectrometer under 1064nm laser excitation.The mechanism of laser absorption of porous layer of AAO film was preliminarily clarified by quantum theory and wave optics.The results of the study are as follows:(1)AAO films of different sizes were prepared by changing the experimental conditions.The samples were characterized by SEM,XRD,Raman spectroscopy and infrared spectroscopy.The results showed that the AAO films were homogeneous,and the pore size distribution was uniform.Analysis displayed that electrochemical polishing could remove the defects of aluminum surface and make the aluminum sheet two oxidation process more stable,but it had little effect on the electrochemical polishing micro ordered aluminum sheet.Reoxidation contributed to the surface defect removal of AAO thin film and formation of highly ordered pore array films.Thickness of porous layer of AAO film increased with the increase of the electrified time,and voltage had a linear relationship with the distance between the pores of AAO film.(2)The plasma characteristics of AAO film excited by 1064nm laser were studied by transient plasma emission spectrometer,the results showed that:under the same laser energy,the full width at half maximum of the spectra decreases with the increase of the delay time and the electron temperature first increase and then decreases.At the same laser energy,the plasma electron density decreases with increasing of delay time because of rapid plasma expansion.Under the same conditions,the electron temperature and the electron density of the laser plasma increase with the increase of the pore size of the AAO film.(3)Laser absorption characteristics of AAO films were measured by laser reflectivity instrument.The results indicated that laser absorption rate of AAO film was larger than that of surface alumina film and absorption rate of the laser increased with the increase of the aperture of the AAO film.The research expands the application direction of porous materials,and provides a new way to enhance the laser coupling efficiency of laser ablation and laser driving.