Design and fabrication of titanium dioxide wire grid polarizer for the far ultraviolet spectral range

Abstract

Nano-optical wire grid polarizers to control the polarization, a fundamental property of light, are of great importance in many optical applications. This importance originates from several advantageous properties, such as large acceptance angle, large clear aperture and simple integration into optical systems. However, due to fabrication and material requirements at short wavelengths particularly in the ultraviolet spectral range the realization is sophisticated. In this contribution we demonstrate the design and fabrication of a titanium dioxide wire grid polarizer for the wavelength range from about 190 nm to 280 nm. Thereby, an unprecedented extinction ratio of 384 and a transmittance of 10 % is achieved at a wavelength of 193 nm and an extinction ratio of 774 and a transmittance of 16% at a wavelength of 248 nm, respectively. Furthermore, the correlation between the polarization performance and a specific feature in the transmittance of transverse-magnetic light which occurs at a wavelength of about 370 nm, i.e. well above the application wavelength, is discussed. The characterization of this feature enables a performance prediction without performing elaborate polarimetry in the far ultraviolet. This facilitates a simple inline or even insitu fabrication process control.