1. A Path to High-Efficiency Optical Coupling for HIRMES.
- Author
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Miller, Timothy M., Brown, Ari-David, Costen, Nicholas, Franz, David, Kutyrev, Alexander, Mikula, Vilem, Miller, Kevin H., Moseley, S. Harvey, Oxborrow, Joseph, Rostem, Karwan, and Wollack, Edward J.
- Subjects
OPTICAL couplers ,BOLOMETERS ,PIXELS ,SURFACE coatings - Abstract
The high-resolution mid-infrared spectrometer (HIRMES) under development for Stratospheric Observatory for Infrared Astronomy is an instrument operating in the 25-122 μm spectral range with a spectral resolution R = Δλ/λ ~ 100,000 and has two absorber-coupled transition edge sensor bolometric detector focal planes. We have developed novel NbTiN low-stress absorber coatings which have the required optical impedance across the HIRMES operating band. The low intrinsic stress of these coatings allow for a peak-to-valley corrugation amplitude < 5 μm of the 450 nm thick, 1.4 mm × 1.7 mm detector pixels. Furthermore, these coatings have a superconducting transition temperature ~ 10 K, which allows them to simultaneously serve as an absorber in the desired signal band and a rejection filter at long wavelengths. This attribute makes them especially attractive for ultrasensitive absorber-coupled bolometric detector applications, because it helps in controlling the optical loading from out-of-band radiation. We also discuss a novel method for integrating a wedged-reflective absorber termination to the detector array. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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