Subwavelength resonant structures designed for long-wave infrared (LWIR) absorption have been integrated with a standard vanadium-oxide microbolometer. Dispersion of the dielectric refractive index provides for multiple overlapping resonances that span the 8-12 μm LWIR wavelength band, a broader range than can be achieved using the usual quarter-wave resonant cavity engineered into the air-bridge structures. Experimental measurements show a 49% increase in responsivity for LWIR and a 71% increase across a full waveband as compared to a similar device designed for only LWIR absorption, using a 300°C blackbody at 35 Hz chopping rate. Increased thermal time constant due to additional mass is shown to lessen this enhancement at higher chopping rates.

Date Published: 20 May 2016
PDF: 7 pages
Proc. SPIE 9819, Infrared Technology and Applications XLII, 98191Q (20 May 2016); doi: 10.1117/12.2223954

Published in SPIE Proceedings Vol. 9819:
Infrared Technology and Applications XLII
Bjørn F. Andresen; Gabor F. Fulop; Charles M. Hanson; Paul R. Norton, Editor(s)