A review of IR transmitting, hollow waveguides

Infrared (IR) transmitting hollow waveguides are an attractive alternative to solid-core IR fibers. Hollow guides are made from plastic, metal, or glass tubes that have highly reflective coatings deposited on the inside surface. These guides have losses as low as 0.1 dB / m at 10.6 mu m and may be bent to radii less than 5 cm. For use in high-power laser delivery applications, the guides have been shown to be capable of transmitting up to 3 kW of CO2 laser power. They are also finding uses in both temperature and chemical fiber sensor applications. This paper reviews the progress in hollow waveguide technology with emphasis on the best guides available today.