Transmission of 1 kW‐class CO2 laser light through circular hollow waveguides for material processing

For the purpose of material processing, we have studied transmission characteristics of germanium‐coated silver hollow waveguides with 1.5 mm φ×80 cm. The maximum input power was 1 kW and the transmission was 90% under straight condition. Steel plates 1.6 mm thick were cut by CO2 laser light through the hollow waveguide and the authors confirmed that this type of waveguide could deliver sufficient laser energy for material processing.