Fabrication methods for infrared resonant devices

Photonic metastructures operating in the 8–13 μm mid-infrared are fast becoming a topic of active research. However, literature describing techniques for their fabrication, which lie on a scale between nanofabrication and microelectromechanical systems technology, is scant. Here, we present detailed fabrication blueprints for achieving robust and repeatable results for devices in this region. Applying a Ge device layer on a ZnS substrate, we fabricate a materially robust transverse-magnetic-polarized wideband reflector with high reflectance in a 2.4 μm band. We then regrow a conformal layer on the device, boosting its performance to yield a ∼3  μm 90% reflectance band from 8.1 μm to 11.1 μm and a band of 98% reflectance spanning 8.7–10.4 μm. The generalized methods presented are applicable in most labs with ordinary fabrication resources.