Study On The Samples Of Femtosecond Laser Micro-nanofabrication

With the development of laser technology, the nanofabrication technologies of optical components are more and more compelling. Materials of laser processing can range from metals, composites, semiconductor materials, organic materials, ceramics, glass and so on. The main content of this thesis is the study of polymer materials in laser nanofabrication, the main contents are as follows:The gold nanoparticals have unique optical, electrical and other properties, which have important application value in the field of optoeletronics, catalysis, and biomedical.We prepared gold nanorods using crystal growth method. Though observing the transmission electron microscopy pictures, we get the length and aspect ratio of gold nanorods. The UV-visible absorption spectra of gold nanorods has two distinct absorption peaks, corresponding to the absorption of the horizontal axis and longitudinal axis of gold nanorods. The main conclusions are as follows:①The aspect ratio of gold nanorods is related to the amount of AgNO3solution.With a certain range, the more AgNO3solution added,the greater of the aspect ratio of gold nanorods.②With the aspect ratio increases, the absorption of longitudinal axis of gold nanorods has a remarkable red shift.Aromatic azo-compound is a potential source of functional materials, in our experiment,the main experimental contents and conclusions are as follows:①We prepared4-aminoazobenzene film and azo-polymer thick film. Interference ripples are produced by linearly polarized800nm and400nm femtosecond pulses, respectively. With proper control of laser energy and irradiation time, the period of interference ripples increases with increasing laser energy. We also got periodic structure in the internal of azo-polymer thick film by linearly polarized400nm femtosecond pulses. The difference is that, long-period ripples are split into short-period ripples, and the specific mechanism still needs further experimental exploration.②Spherical nanoparticles with dimameter about200nm are formed after irradiation with circularly polarized400nm femtosecond pulses.③Alignment of nanoparticles is obtained after irradiation with 400nm and800nm linearly polarized femtosecond laser simultaneously. We explore the influence of the laser energy and pulse numbers on the formation of interference ripples and particle morphology. We discuss the possible physical mechanism of photo-isomerization phenomenon.Studying a new type of photoresist, improving the laser processing precision with the principle of polymerization and polymerization suppression have been the frontier of international laser nanofabrication in the last three years. The new negative-tone photoresist were prepared by mixing ITX and EDAB into the monomer pentaerythritol triacrylate (1.5%wt respectively). This monomer contains300-400ppm monomethyl ether hydroquinone as inhibitor. The laser beam of800nm is used to initiate polymerization in the negative-tone photoresist. The laser beam of532rim is used to deactivate the photo initiator, preventing polymerization. Combining with the Jablonski diagram,the absorption and fluorescence spectra of ITX, we analyze the mechanism of polymerization, which lays the foundation for looking for the new photoinitiator.