Synthesis And Properties Of Thin Films For Hollow-core Fiber Application In Ultraviolet Laser Delivery

The bright prospect of applications for ultraviolet laser in medical laser surgery, material processing etc. is presently limited by the lack of efficient delivery tools. Therefore, there is an urgent need of manufacturing fiber with excellent performances.The nanometer composite materials, formed by inlaying metal with a nanometer size(especially for Au, Ag, Al, and Cu etc.) into inorganic medium(like glass, ceramics etc.), have some optics and electrical properties different from block materials. As for these properties, this kind of nanometer composite materials has a very wide prospect of applications, like photoelectric thin films, optical waveguide element, optical switch and solar battery. Based on these excellent properties of metal- inorganic nanometer composite materials, this article is trying to preparation of thin film layer for hollow-core fibers delivering ultraviolet laser, to dispersing Au into SiO₂ then formed Au-SiO₂ nanometer composite thin film materials, and also some study on its properties.The experiment's main chemicals are ethyl orthosilicate (TEOS) and chloroauric acid (HAuCl₄·4H₂O), using alcohol (EtOH) and H₂O as for dissolvent, using N,N-dimethylformamide (DMF) as for Drying Control Chemical Additives (DCCA), using chlorhydric acid (HCl) as for accelerant. Au-SiO₂ composite Sol formed by the Sol-Gel technique, then preparation for the Au-SiO₂ nanometer composite thin film by dip-coating method.The preparation for Au-SiO₂ nanometer composite thin film is based on silicon Sol, so a list of formula for substrate silicon Sol, fit for long-term plated film, should be confirmed. Using orthogonal experiment design, a advisable formula for substrate silicon Sol is completed: n (TEOS) : n (EtOH) :n (H₂O) :n (DMF) =1:6:10:1 , pH=1.5. With TEM test, comparing substrate silicon Sol with Au-SiO₂ composite Sol, then observing and analyzing their differences, confirm the exist state and reducing manner of Au in the Au-SiO₂ composite Sol. TEM test demonstrates that Au exists in Au-SiO₂ composite Sol with a state of [AuCl₄]^- , it also decides the reducing manner of Au: [AuCl₄]^--AuCl₃-AuCl-Au.XRD Test analyzes Au-SiO₂ nanometer composite thin film with a Au/Si=0.2% doping concentration, different temperature heat processing and different dip-coating frequency. It demonstrates that the Au-SiO₂ composite thin film, with 600℃/30min heat processing and 3 times dip-coating, has a stronger diffraction peak near 20=38.09°, it matches the standard XRD spectrum of Gold (Au). The particle size of Au is about 25nm, inlayed in SiO₂ host uniformly and discontinuously. SEM test analyzes Au-SiO₂ nanometer composite thin film, with a Au/Si=0.2% doping concentration, 600℃/30min heat processing and different dip-coating frequency, it demonstrates that composite thin film has a uniform and compact surface with 3 times dip-coating, also the inlay of Au shows good.