Design of angularly tolerant zero-contrast grating filters for pixelated filtering in the mid-IR range
Résumé
Zero-contrast gratings (ZCG) can be used to implement narrow bandpass transmission filters. However, they suffer from a poor angular tolerance which hinders their use in pixelated applications. Combining ZCG with double-corrugation grating, we increase the resonance width and the angular tolerance of the filter by more than one order of magnitude. Filters tunable around 4.6μm with more than 90% transmission and compatible with 140μm pixel size are demonstrated.