Room Temperature VOx Air-Bridge Bolometer integrated with Metal-Insulator-Metal Resonant Absorbers

Spectrally-selective un-cooled micro-bolometers have many military and industrial applications for infrared sensing and imaging, e.g. target acquisition and chemical analysis. In this work, a micro-bolometer was fabricated with integrated wavelength-selective absorber based on subwavelength metal-insulator-metal (MIM) resonators. The fabricated air-bridge structure used a vanadium oxide thin film as the bolometric element. A novel aqueous deposition method of depositing vanadium oxide was investigated and compared to traditional sputtered vanadium oxide to determine achievable temperature coefficient of resistance. The MIM absorber itself was investigated as a function of the dielectric used, and the strong dependence of the resonance spectrum on dispersion was revealed. Finally, the completed bolometers were characterized, and usual figures of merit for thermal infrared detectors were determined. Unlike previous efforts this research is aimed at putting the bolometer inside of the MIM absorber, thereby reducing thermal mass and the thermal time constant compared to those bolometers where the absorbers are just put on top