Unfortunately, many optical materials transparent to visible light become strongly absorbing in the ultraviolet (UV) spectral region (200-400nm). Also due to the shorter wavelengths – scattering effects are very strong in the UV region. Consequently, to minimise these effects, manufacturing UV lenses with tight tolerances and high surface quality (λ/10 p-v or better) is much more critical than with visible or IR optics.
Learn more: https://www.resolveoptics.com/uv-lenses-pros-and-cons/
