High‐performance integrated mid‐infrared filter arrays

A static filter array is developed based on Fabry–Perot cavities operating in the mid‐infrared range from 2 to 4.5 µm, matching the absorption region of several gases relevant for air quality monitoring. The filters include two distributed Bragg reflectors and a high‐index tuning element with varying thickness in between. The filters display high peak transmittance () and controllable peak width. The robustness, ease of fabrication and the possibility to tune the optical response to a specific application make the integrated filter arrays suitable for compact sensing systems.