Materials Pushing the Application Limits of Wire Grid Polarizers further into the Deep Ultraviolet Spectral Range

摘要

Wire grid polarizers (WGPs), periodic nano-optical meta-surfaces, areconvenient polarizing elements for many optical applications. However, they arestill inadequate in the deep ultraviolet spectral range. We show that toachieve high performance ultraviolet WGPs a material with large absolute valueof the complex permittivity and extinction coefficient at the wavelength ofinterest has to be utilized. This requirement is compared to refractive indexmodels considering intraband and interband absorption processes. We elucidatewhy the extinction ratio of metallic WGPs intrinsically humble in the deepultraviolet, whereas wide bandgap semiconductors are superior materialcandidates in this spectral range. To demonstrate this, we present the design,fabrication and optical characterization of a titanium dioxide WGP. At awavelength of 193 nm an unprecedented extinction ratio of 384 and atransmittance of 10 % is achieved.