Microbolometers for infrared detection

Abstract

We describe a novel room‐temperature detector for the wavelength range 10–1000 μm. This detector consists of a thin bismuth bolometer film with dimensions much smaller than a wavelength. The small size of the detector results in reduced NEP and faster response. A video NEP of 1.6×10⁻¹⁰ W/Hz^1/2 is obtained at 119 μm, remaining within a factor of 10 of this value for modulation frequencies up to 25 MHz. When used as a mixer, the device is predicted to have an NEP of 3.5×10⁻¹⁸ W/Hz. It is easily fabricated with conventional planar processing techniques and can be replicated in arrays. The device is expected to be most useful when the radiation to be detected is spatially coherent.