Fabrication of Doubly-Corrugated Zero-Contrast-Grating for Broadband Pixelated Filtering in the Mid-IR Range

摘要

Zero-contrast grating filters (ZCG) car be used to implement efficient bandpass transmission filter with narrow bandwidths of a few nanometers. In a precedent article [1], we have illustrated the validity of the ZCG approach for the mid-IR range using germanium and calcium fluoride, as well as the possibility to increase both the bandwidth and the angular acceptance of such filters by a decade or more using a double corrugation scheme for the grating. However, when it comes to fabricating such devices, conventional semiconductor methods cannot be straightforwardly applied because of the specific requirements of the infrared materials used. Adapting specific methods of the semiconductor industry, we manage to fabricate such devices. A first optical characterization is performed.