Abstract
We present new, to the best of our knowledge, large-scale, high-quality spectral filters operating in the long-wave infrared (LWIR) spectral region. We employ high-spatial resolution nanofabrication techniques to achieve large-area (${12}\;{{\rm mm}} \times 12\;{{\rm mm}}$) spectrally tunable notch filters. Filter operation is based on the guided-mode resonance effect. The device structure consists of a germanium waveguide grating on top of a zinc selenide substrate. The filters reflect the incident broadband light at one (or more) narrow spectral bands while fully transmitting the rest. We tune the reflected wavelength by tilting the filter. Filters based on one-dimensional gratings are polarization sensitive. We fabricate prototype filters and characterize their polarization dependence and spectral tuning performance using a tunable quantum cascade laser system that spans the $\sim{7 - 13}\;\unicode{x00B5}{\rm m}$ spectral band. We obtain an excellent agreement between the theoretical and experimental results.
© 2021 Optical Society of America
Full Article | PDF ArticleMore Like This
Y. H. Ko, K. J. Lee, S. Das, N. Gupta, and R. Magnusson
Opt. Lett. 46(6) 1329-1332 (2021)
K. J. Lee, Y. H. Ko, N. Gupta, and R. Magnusson
Opt. Lett. 45(16) 4452-4455 (2020)
Neelam Gupta and Junyeob Song
Opt. Continuum 2(1) 197-204 (2023)