Metamaterial microbolometers for multi-spectral infrared polarization imaging

Area of Science:

• Optics and Photonics
• Materials Science
• Infrared Technology

Background:

• Vanadium oxide (VOx) microbolometers are key components for uncooled mid-infrared imaging.
• Conventional microbolometers lack spectral selectivity and polarization sensitivity, requiring bulky external filters.
• Existing systems for spectral and polarization filtering are complex and increase detector size.

Purpose of the Study:

• To demonstrate the integration of metamaterial absorbers (MAs) with VOx microbolometers.
• To simultaneously tailor spectral and polarization responses of microbolometer detectors.
• To mitigate the need for separate spectral filters and polarizers in infrared imaging systems.

Main Methods:

• Design and fabrication of metamaterial absorbers (MAs) with sub-wavelength resonators.
• MAs selectively absorb TM-polarized light within tunable spectral bands.
• Integration of MAs with VOx microbolometers and characterization of detector performance.

Main Results:

• Fabricated MAs achieved high TM absorption (0.8322 and 0.7720) in specific mid-infrared bands.
• High polarization extinction ratios (PER) of 42.24 and 42.65 were obtained.
• Integrated detectors showed responsivities of 1.0 V/W at 6.0 µm and 1.46 V/W at 6.8 µm, with high D* values.

Conclusions:

• Metamaterial absorbers effectively enable simultaneous spectral and polarization selectivity in VOx microbolometers.
• This approach simplifies infrared detector design, reducing system complexity and bulk.
• The technology advances the development of large-format, room-temperature, multi-spectral infrared polarization imaging detectors.