Thickness and uniformity of fluorocarbon polymer film dynamically coated inside silver hollow glass waveguides

The variation in properties of a fluorocarbon polymer (FCP) film during a drying-curing process is investigated for fabricating FCP-coated silver (FCP/Ag) hollow glass waveguides. A dynamic liquid-phase coating procedure is used. Through the analyses of the loss spectra of hollow waveguides made in various conditions, a relationship between the thickness of the FCP film and the coating velocity is obtained. The optimum fabrication condition is also established for producing FCP/Ag hollow glass waveguides for the mid-IR.     

High-peak-power, pulsed CO(2) laser light delivery by hollow glass waveguides

Flexible hollow glass waveguides with internal metallic and dielectric coatings have been used to deliver high-peak-power transversely excited atmosphere CO(2) laser energy. The straight guide loss is as low as 0.17 dB/m for 1000-mum-bore guides and 0.46 dB/m for 530-mum-bore guides propagating the HE(11) mode. The loss increases to 0.93 and 1.36 dB/m, respectively, when guides are bent to a radius of 0.25 m. The hollow glass waveguides have been used to deliver pulsed CO(2) laser energy successfully with a peak power of 0.7 MW and an energy of 350 mJ per pulse with a gas purge through the hollow core. The delivered average power is as high as 27 W. It is concluded that these waveguides are promising candidates for pulsed CO(2) laser delivery in medical and surgical applications.     

Fabrication of hollow waveguides for CO2 lasers

Germanium-coated metal (silver, gold, and copper) hollow waveguides for CO(2) laser energy delivery have been fabricated by electron-beam evaporation and plating techniques in which an acid-soluble glass mandrel with small surface roughness was used. The transmission characteristics of Ge-coated metal hollow waveguides were studied. Ge-coated Ag hollow waveguides showed smaller loss, 0.2 dBm, for CO(2) laser light than Ge-coated Au and Cu waveguides. The transmission characteristics of Ge-coated Ag hollow waveguides were measured in relation to a core diameter and a bending radius.     

Hollow fiber optics with improved durability for high-peak-power pulses of Q-switched Nd:YAG lasers

To improve the damage threshold of hollow optical waveguides for transmitting Q-switched Nd:YAG laser pulses, we optimize the metallization processes for the inner coating of fibers. For silver-coated hollow fiber as the base, second, and third Nd:YAG lasers, drying silver films at a moderate temperature and with inert gas flow is found to be effective. By using this drying process, the resistance to high-peak-power optical pulse radiation is drastically improved for fibers fabricated with and without the sensitizing process. The maximum peak power transmitted in the fiber is greater than 20 MW. To improve the energy threshold of aluminum-coated hollow fibers for the fourth and fifth harmonics of Nd:YAG lasers, a thin silver film is added between the aluminum film and the glass substrate to increase adhesion of the aluminum coating. By using this primer layer, the power threshold improves to 3 MW for the fourth harmonics of a Q-switched Nd:YAG laser light.     

AgI-coated silver-clad stainless steel hollow waveguides for infrared lightwave transmission and their applications

We fabricated silver iodide (AgI)-coated silver hollow waveguides to transmit a wide range of infrared (IR) light. Silver-clad stainless steel pipes were used as a supporting pipe. Since this type of metallic hollow waveguide has high mechanical strength and heat resistance, it is suitable as a rigid lightwave probe for various applications such as dental or medical laser treatment, IR spectroscopy, thermal radiometry, and laser processing. Considering these applications, we estimated the hollow waveguides with different thicknesses of the AgI layer. By optimizing the AgI layer thickness according to the wavelength of propagating light, we succeeded in efficiently transmitting Er-YAG and CO(2) laser light. We also studied the optical characteristics of a wide range of incoherent light for IR spectroscopy and radiometry applications using these metallic hollow waveguides as lightwave probes.     

介质(Ag/AgI)镀层空芯玻璃光纤的制备及红外传输性能的研究

介质（Ａｇ／ＡｇＩ）镀层空芯玻璃光纤是一种较好的传输红外激光的柔性光纤材料．采用液相化学沉积法成功地制备了内径分别为１．０、０．５３、０．３２ｍｍ,长度为１．５ｍ的介质（Ａｇ／ＡｇＩ）镀层玻璃空芯光纤．利用傅里叶红外光谱仪和 ＬＪＬ－３５Ａ ＣＯ_２激光器分别测试了介质（Ａｇ／ＡｇＩ）镀层玻璃空芯光纤的传输损耗,测试结果表明：介质（Ａｇ／ＡｇＩ）镀层空芯玻璃光纤在２．５～２０μｍ波长范围内有较低的损耗值;随着光纤内径（α）的增大,空芯光纤的传输损耗（α）降低,这与Ｍｉｇａｇｉ理论（α　∝１／α^３）相符合．另外,由于光纤的注入端头发热致使介质（Ａｇ／ＡｇＩ）镀层空芯玻璃光纤的传输损耗随注入功率的增加而增大．     

Optical properties of small-bore hollow glass waveguides

Hollow glass waveguides with a 250-μm i.d. have been fabricated with a liquid-phase deposition technique that uses silica tubing as a base material. The losses of the 250-μm-bore guide measured at CO(2) laser wavelengths are as low as 2.0 dB/m. The straight losses for the hollow guides are in good agreement with theoretically predicted losses as a result of the nearly ideal structure of the guides. It is also shown that the guides have low bending losses, a nearly pure-mode delivery, and good high-power laser transmission. By proper design of the dielectric thickness, the guide is also able to deliver Er:YAG laser energy with a low loss of 1.2 dB/m for the 320-μm-bore waveguide. Because the hollow glass waveguide is very flexible and robust, it is quite suitable for medical applications.     

Refractive indices and extinction coefficients of polymers for the mid-infrared region

Refractive indices and extinction coefficients of several polymers have been measured for the wide infrared wavelength region. The polymers used as coating materials have also been found useful for low-loss hollow waveguides for the transmission of Er:YAG, CO, and CO(2) laser light, respectively.     

水性建筑反射隔热涂料的研制

利用纯丙和苯丙乳液为基料,制备了具有热反射和低导热协同作用的隔热涂料。通过对颜填料太阳光反射率和隔热性能的研究,选择以空心玻璃微珠和金红石型二氧化钛为颜填料,空心微珠的最优含量为4%～10%(wt)。研制建筑反射隔热涂料基础性能优异,可见光反射比达到90%以上,半球发射率大于85%,隔热指数大于60%。     

空心玻璃微珠用量对涂料反射和隔热性能的影响(英文)

本文通过空心玻璃微珠涂料反射实验、隔热实验和SEM分析研究空心玻璃微珠用量对涂料反射和隔热性能影响,结果表明:空心玻璃微珠的适宜添加量为25%,反射率能达45%-65%,能降温9℃;涂料反射隔热性能主要是由空心玻璃微珠对太阳光具有反射和阻隔作用引起,其次还与空心玻璃微珠在涂层表面的排布有关。在空心玻璃微珠用量为25%时,空心玻璃微珠在涂层中形成由无数空腔形成的致密的阻隔层来反射太阳光和阻止热传导。     

Fabrication of a polymer-coated silver hollow optical fiber with high performance

The techniques for fabricating a hollow optical fiber with an inner silver layer and a cyclic olefin polymer (COP) layer have been improved to reduce the surface roughness of these two layers. The loss spectrum was thereby drastically reduced over a wide wavelength range, from visible to near infrared. Optimization of the COP layer thickness resulted in low loss simultaneously at several key laser wavelengths. Infrared hollow fiber with low loss was developed for Er:YAG and Nd:YAG lasers. It can also deliver green and red pilot beams with low loss. Use of this fiber in therapeutic and pilot lasers should prove useful for research and development in laser medicine.     

耐高温防腐隔热涂料的制备与性能

耐高温防腐隔热涂料在石化管道领域具有重要的应用。文中以环氧改性有机硅树脂为基料,通过复配具有优异隔热性能的空心玻璃微珠、低温熔融玻璃粉、润湿分散剂、消泡剂等制备了一种至少耐500℃高温的防腐隔热涂料。利用扫描电子显微镜、热导分析、电化学阻抗谱,研究了不同颜基比、空心玻璃微珠含量对涂料力学性能和热学性能的影响。研究表明,颜基比为2/1,空心玻璃微珠占填料比例为40%时涂层综合性能达到最佳。     

Preparation and characterization of hollow glass microspheres coated by CoFe2O4 nanoparticles using urea as precipitator via coprecipitation method

The composite of hollow glass microspheres coated by CoFe₂O₄ nanoparticles has been successfully prepared using urea as precipitator via coprecipitation method. The resultant composites were characterized by X-ray diffraction, field emission scanning electron microscope and vibrating sample magnetometer. The results showed that the slow decomposition of urea could be beneficial to form uniform and entire cobalt ferrite coating layer on the surface of hollow glass microspheres. The smoothest morphology was obtained for the sample prepared from 0.7 M urea, while the sample prepared from 1.0 M urea had the thickest shell. This indicated that there was a competition between the morphology and thickness of the coated microspheres. A possible formation mechanism of hollow glass microspheres coated with cobalt ferrite was proposed. The magnetic properties of the samples were also investigated.     

一种新型隔热涂料的制备及性能研究

以苯丙乳液为成膜剂,硅烷偶联剂处理后的中空玻璃微珠为功能隔热填料合成新型的隔热涂料。结果表明,用硅烷偶联剂预处理中空玻璃微珠后涂料附着力能提高1个级别;涂层导热系数随中空玻璃微珠粒径的增加呈现先减小后增大的趋势,当中空玻璃微珠的粒径为58μm左右时导热系数比其它粒径制得涂料的导热系数降低6%～28%;随涂膜厚度的增加,隔热效果增强,但当涂膜厚度增大到0.3mm时,继续增加涂膜厚度,隔热效果几乎不再增强;当中空玻璃微珠含量小于10%时,热反射率随中空玻璃微珠在隔热涂料中含量的增加显著增加,超过10%后,热反射率增加速率减缓,当达到12%时,涂料的热反射率值最高,继续增加玻璃微珠含量,热反射率几乎不增加。     

Power delivery of free electron laser light by hollow glass waveguides

Hollow glass waveguides are used to deliver free electron laser (FEL) energy for applications in medicine and laser surgery. The hollow guides, optimized for the delivery of 6.45-μm FEL radiation, exhibited losses for the 1000-μm bore as low as 0.39 dB/m when the guide was straight and 1.75 dB/m when bent to a radius of 25 cm. Hollow glass guides are flexible, and their broadband capability provides an ideal fiber optic for the tunable FEL.     

Processing and characterization of silver films used to fabricate hollow glass waveguides

Hollow glass waveguides are an increasingly popular fiber for the delivery of high-power IR laser radiation. At CO(2) laser wavelengths the measured and theoretical losses agree, but at the 3-microm Er:YAG laser wavelength the losses remain higher than expected. The reason for this is the surface roughness of the silver film used to form the first layer of the Ag/AgI thin-film structure. We found that the roughness of the silver film increases fivefold as silvering times increase from 5 to 80 min. This increased surface roughness produces a concomitant linear increase in the attenuation coefficient for the silver-only guides for wavelengths shorter than approximately 5 microm.     

Deposition of biomimetic biocompatible oxides on metallic glass surface by electro-discharge coating process

Bulk metallic glass demonstrates superior mechanical properties and excellent bio-mechanical stability compared to routinely used biomaterials like titanium, cobalt-chromium, stainless steel, et cetera. However, the metallic glass surface do not easily adhere to the leaving tissues due to native bio-inert oxide layer, which have poor wear resistance and low hardness. In this current study an innovative method for surface coating of bulk metallic glass by mixing hydroxyapatite powder during electro-discharge machining has been employed. A biomimetic nano-porous bio-ceramic layer of oxides and carbides was deposited on metallic glass surface. The modified surface integrity and composition were investigated by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction characterization techniques. The characterization results confirmed the formation of a natural bone-like nano-porous surface topography on the metallic glass surface using a novel hydroxyapatite-mixed electro-discharge coating process. In addition, a favourable surface chemistry in the form of bioceramic carbides (zirconium carbide, titanium carbide) and zirconium oxide layers, was achieved.     

Abriebschutzbeschichtung von Kunststoffen durch plasmaaktivierte Hochratebedampfung. Abrasion Resistant Coatings on Plastics by Plasma Activated High Rate Deposition

Transparent plastics, e.g. PMMA or Polycarbonate, have low weight, optical clarity and processing benefits of a thermoplastic. A great disadvantage of such plastics is the lack of abrasion resistance. Therefore the plastics have to be protected for practical application. SiO₂ layers perform very well as clear abrasion resistant layers. The typical layer thickness ranges from 1 μm to 6 μm depending on the required abrasion resistance. To get an abrasion resistance comparable to float glass a layer thickness of about 6 μm for SiO₂ layers is needed. The layers are deposited by the HAD‐process (hollow cathode activated deposition). There the coating material is evaporated by an electron beam and is deposited on the substrate by adding reactive gases (e.g. O₂, N₂O or organic monomers) at the presence of an intensive plasma. A special hollow cathode, adapted to this process, is used as plasma source. The typical deposition rates are 300 nm/s to 600 nm/s for the deposition of SiO₂.     

空心玻璃微珠含量比对涂料隔热性能的影响

主要研究了自主研制的空心玻璃微珠涂料的隔热性能。通过隔热模型试验，考察了空心玻璃微珠涂料的隔热性能，对比了空心玻璃微珠含量比对涂料隔热性能的影响，并对其隔热机理和含量比的影响原因进行了探讨。指出空心玻璃微珠涂料是一种具有良好隔热性能的涂料，能产生明显的隔热效果，但过高的空心玻璃微珠含量比将对隔热性能产生劣化影响。     

Infrared transmissive, hollow plastic waveguides with inner Ag-Agl coatings

Hollow polycarbonate waveguides with thin-film coatings of Ag-AgI were fabricated by liquid-phase chemistry methods. These hollow waveguides, which have bore sizes ranging from 500 to 2000 microm and lengths as long as 2 m, are transmissive from 2 to more than 20 microm. The lowest loss of 0.02 dB/m was obtained for a straight 2000 microm bore guide at 10.6 microm. This is to our knowledge the lowest loss measured for any IR fiber at CO2 laser wavelengths. The bending losses were found to increase as 1/R, where R is the radius of the bend. These waveguides were able to withstand 18 W of CO2 laser input power for bore sizes greater than 1000 microm.