Micro-electromechanical-system-tuned resonant filters spanning the 8–12 µm band
Abstract
The spectral band covering ∼ 8 − 12 µ m is atmospherically transparent and therefore important for terrestrial imaging, day/night situational awareness systems, and spectroscopic applications. There is a dearth of tunable filters spanning the band. Here, we propose and demonstrate a new, to the best of our knowledge, tunable-filter method engaging the fundamental physics of the guided-mode resonance (GMR) effect realized with a non-periodic lattice. The polarization-dependent filter is fashioned with a one-dimensional Ge grating on a ZnSe substrate and interrogated with a ∼ 1.5 m m Gaussian beam to show clear transmittance nulls. To expand the tuning range, the device parameters are optimized for sequential operation in TM and TE polarization states. The theoretical model exhibits a tunable range exceeding 4 µm, thus covering the band fully. In the experiment, a prototype device exhibits a spectral range of 8.6–10.0 µm in TM and 9.9–11.7 µm in TE polarization or > --> 3 µ m total. With additional efforts in fabrication, we expect to achieve the full range.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 10, 2021
- Source ID
- 10.1364/ol.418545
Entities
People
- K. J. Lee
- Natasha Gupta
- Robert Magnusson
- Subrata Das
- Y. H. Ko
Organizations
- United States Army Research Laboratory
- University of Texas at Arlington