Fabrication of polarization colour filter device via direct Au film imprinting

Abstract

In this study, Au grating with a subwavelength period was fabricated on low-melting glass via direct imprint lithography. The Au film was imprinted at 425 °C and 5 kN using SiC as a mold. The period, grating depth, and fill factor of the mold were 300 nm, ∼240 nm, and 0.5, respectively. Consequently, Au grating with a pitch, depth, and fill factor of 300 nm, ∼110 nm, and 0.7, respectively, was obtained. The transverse magnetic (TM, electric field vector perpendicular to the grating) spectra at an incident angle of 40° exhibited sharp peaks at a wavelength of 642 nm, and the TM transmittance and extinction ratio were 30% and 12.9 dB, respectively. The maximum extinction ratio was 19.0 dB at a wavelength and incident angle of 1 µm and 60°, respectively. This process is simpler and less expensive than the conventional fabrication processes.