Atomic layer deposition for hafnium oxide-based meta-optics in the ultraviolet spectral range

Hafnium oxide (HfO₂) is of increasing interest in both microelectronics and photonics due to its favorable optical and dielectric properties. In particular, its high refractive index, wide bandgap, and chemical stability render it attractive for optical coatings and metasurfaces down to the ultraviolet spectral range. Atomic layer deposition (ALD) has been commonly employed to produce high-quality HfO₂ films. In this contribution we are reporting on the measured refractive index from a wavelength of 120 nm to 600 nm.