The ability of narrow bandpass filters to discriminatewavelengths between closely-separated gas absorption lines is crucial inmany areas of infrared spectroscopy. As improvements to the sensitivity ofinfrared detectors enables operation in uncontrolled high-temperature environments, this imposes demands on the explicit bandpass design to provide temperature-invariant behavior. The unique negative temperature coefficient (dn/dT<0) of Lead-based (Pb) salts, in combination with dielectric materials enable bandpass filters with exclusive immunity to shifts in wave length with temperature. This paper presents the results of an investigation into the interdependence between multilayer bandpass designand optical materials together with a review on invariance at elevated temperatures.
- Thin films, optical properties.
- Spectral properties
- Multilayer design
- Filters, interference
- Spectroscopy, infrared
Stolberg-Rohr, T. K., & Hawkins, G. J. (2015). Spectral design of temperature-invariant narrow bandpass filters for the mid-infrared. Optics Express, 23(1), 580-596. https://doi.org/10.1364/OE.23.000580