Nanofabrication And Coloration Of Metal Film Via Single-pulse Femtosecond Laser Writing

Utilization of structural colors produced by metallic nanostructures is expected to revolutionize the current display technologies based on an inkjet or a pigmentationbased color printing.In the past two decades,researchers have found in the experimental study of metal film processing by femtosecond laser writing that the light(reflection,transmission or scattering)passing through the metal nanostructures has significant selective resonance absorption characteristics in the visible band,which can be manifested as color display on the macro level.Femtosecond laser nanofabrication of nanostructures on the metal film technique has replaced gradually some traditional fabrication techniques because of its the small thermal-affected zone,higher resolution and other obvious advantages.And,metallic nanostructure fabricated by femtosecond laser writing has become a research focus with the special property of color generation and modulation.Based on the principle of femtosecond laser nanofabrication technique and the color modulation by metallic nanostructures,this thesis carried out the research on the metallic nanostructures,such as nanohole and nanobubble on the metaldielectric-metal(MIM)film using the femtosecond laser writing technique,and the generation mechanism of structure-colors.The main research contents are listed as follows:Firstly,we described the interaction mechanism between laser and metal materials,liquid explosion theory and fluid dynamics theory,and analyzed the evolution of excitation,ionization,expansion and jetting of metal films after femtosecond pulsed laser irradiation from different aspects.Secondly,we used a Ti-sapphire femtosecond laser as a processing light source with a center wavelength of 800 nm and a repetition rate of 1K hertz.We have done a back ablation research experiment,which can provide a large-scale and high-efficiency nanobubble and nanohole arrays on the surface of MIM multi-layer film structures using the single-point—single-pulse—line-scan laser fabrication method.Thirdly,we investigated the color property of metallic nanostructure by the characterization of nanobubbles and nanoholes,and analyzed the influences of the single pulse laser energy density and dot array processing cycle on the structure colors.At last,we introduced the CIE1931-XYZ chromaticity coordinate system to investigate the structure colors of the metallic nanobubbles and nanoholes on the MDM structure.Then according to the spectral data of the structure scattered light measured with dark field microscope and spectrometer,we calculated the tristimulus values of spectral colors,chromaticity coordinates and CIE1931 chromaticity diagram.In addition,the main wavelength color was also investigated.