Tunable mid-wave infrared Fabry-Perot bandpass filters using phase-change GeSbTe.
Accepted version
Peer-reviewed
Repository URI
Repository DOI
Change log
Authors
Williams, Calum https://orcid.org/0000-0002-6432-6515
Hong, Nina
Julian, Matthew
Borg, Stephen
Kim, Hyun Jung
Abstract
We demonstrate spectrally-tunable Fabry-Perot bandpass filters operating across the MWIR by utilizing the phase-change material GeSbTe (GST) as a tunable cavity medium between two (Ge:Si) distributed Bragg reflectors. The induced refractive index modulation of GST increases the cavity's optical path length, red-shifting the passband. Our filters have spectral-tunability of ∼300 nm, transmission efficiencies of 60-75% and narrowband FWHMs of 50-65 nm (Q-factor ∼70-90). We further show multispectral thermal imaging and gas sensing. By matching the filter's initial passband to a CO2 vibrational-absorption mode (∼4.25 µm), tunable atmospheric CO2 sensing and dynamic plume visualization of added CO2 is realized.
Description
Keywords
physics.optics, physics.optics, cond-mat.mtrl-sci, physics.app-ph
Journal Title
Opt Express
Conference Name
Journal ISSN
1094-4087
1094-4087
1094-4087
Volume Title
28
Publisher
Optica Publishing Group
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Rights
All rights reserved
Sponsorship
Cancer Research UK (24669)
Engineering and Physical Sciences Research Council (EP/R003599/1)
Engineering and Physical Sciences Research Council (EP/R003599/1)
H.J.K and S.B acknowledge support from the NASA LaRC CIF/IRAD Program. C.W. acknowledges support from the Cancer Research UK Pioneer Award (C55962/A24669), Engineering and Physical Sciences Research Council (EP/R003599/1) and through the Wellcome Trust Interdisciplinary Fellowship.