Fabrication of cyclic olefin polymer (COP)-coated silver hollow glass waveguides for the infrared

Cyclic Olefin Polymer (COP)-coated silver hollow glass waveguides were proposed and fabricated for infrared laser light transmission such as Er:YAG, CO, and CO₂ lasers. Silver mirror reaction and liquid-flow coating technique were employed to form the silver and dielectric layers inside the fused glass capillary tube for the simplicity, lower cost and potentiality of mass-production. Hollow waveguides with the length of 2m and the inner diameters of 700 μm and 1mm have been successfully fabricated. It is shown that COP-coated silver hollow glass waveguides can be used to transmit Er:YAG, CO, and CO₂ laser light with low losses when the thickness of COP layer is properly chosen. The measured spectra in the visible and mid-infrared regions also show that uniform films were deposited inside the tube. Comparisons were also made among the waveguides that were inner-coated with other dielectric materials used before.