Polarization independent electron-beam written 2-D longwave infrared guided-mode resonant filters

We fabricated guided mode resonance filters (GMRFs) with two-dimensional (2-D) gratings operating in the 8 to 12 pm long-wave infrared (LWIR) region by depositing amorphous germanium (Ge) film to form a zero-contrast (ZC) waveguide-grating (WGG) on polished zinc selenide (ZnSe) substrates with and without antireflection coating (ARC). We employed high -spatial resolution e-beam lithography and reactive-ion etching (RIE) nanofabrication techniques. We characterized the fabricated filters for their polarization independent spectral performance using a tunable quantum cascade laser (QCL) system and a modified Fourier transform infrared (FTIR) spectrometer. Here, we will present both theoretical and experimental results and their comparison.(c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement