We have designed, fabricated and tested narrow-band Fabry-Perot filters in the infrared using gold porous mirrors and a silicon spacer layer. The filter peaks at 10 mu m and 15 mu m have approximately 10% transmission and a 1.5% linewidth. A Fabry-Perot structure with plane metal layers having a similar linewidth would have a transmission of only 0.2%. Thus, for the same linewidth we have improved the transmission by a factor of 50. Apart from the optical enhancements, these filters also have the advantage that they can be made inexpensively in a standard silicon MEMS technology and that their resonances can be finely tuned through postprocessing.
in Moems and Miniaturized Systems Xvii. vol. 10545 (Issue), W. Piyawattanametha, Y. H. Park, and H. Zappe, Eds., ed Bellingham: Spie-Int Soc Optical Engineering, 2018.