Guidance of ultraviolet light down to 190 nm in a hollow-core optical fibre

We report an anti-resonant hollow core fibre with ultraviolet transmission down to 190 nm, covering the entire UV-A, UV-B and much of the UV-C band. Guidance from 190 – 400 nm is achieved apart for a narrow high loss resonance band at 245 – 265 nm. The minimum attenuation is 0.13 dB/m at 235 nm and 0.16 dB/m at 325 nm. With an inscribed core diameter of ∼12 µm, the fibre’s bend loss at 325 nm was 0.22 dB per turn for a bend radius of 3 cm at 325 nm.