Hollow-core fibers with reduced surface roughness for record losses and beam delivery in the UV domain

We report a new generation of HCPCFs demonstrating ultralow loss in the short-wavelength domain by the use of new fabrication process. The process consists of applying a shear stress on the fiber silica core-surround surface. This approach allows a significant silica surface roughness reduction demonstrated by using a home-made picometer-resolution and high dynamic range profilometer. The surface quality improvement is further corroborated by record optical performances measured in the UV spectral range with losses between $50-10 \mathrm{~dB} / \mathrm{km}$ in the wavelength range of $280-400 \mathrm{~nm}$. As a demonstration of the interest of such fibers, UV laser beam delivery at specific industrial wavelengths including 257/266 nm and $343 / 355 \mathrm{~nm}$ are presented.