Infrared hollow glass waveguides fabricated by chemical vapor deposition

Hollow glass waveguides have been fabricated for the delivery of infrared radiation by chemical vapor deposition methods. A molybdenum film is first deposited inside 700-microm silica tubing by the hydrogen reduction of molybdenum chloride. Then a zinc sulfide or aluminum oxide film is deposited onto the molybdenum layer. These dielectric films enhance the reflectivity, and we observe a reduction in loss for the thin-film combination compared with the molybdenum film alone. The chemical vapor deposition techniques may be extended to the fabrication of hollow guides with multiple dielectric layers that have much lower losses than current single-layer designs.