High temperature superconductor bolometers for spectral imaging of cold planetary objects

The 2013 Planetary Science Decadal Survey recommends a number of missions that require thermal imaging and compositional analysis the surfaces of cold bodies to gain understanding about the origins and evolution of the solar system and possible habitable climates therein. In response, we propose development of superconducting bolometer arrays for the focal planes of thermal imagers. Working in combination with a wavelength dispersive element such as an Offner grating or a FTIR spectrometer, these arrays are sensitive enough to provide thermal images with hyperspectral wavelength resolution of each spatial pixel of objects such as the icy moons of Jupiter and the cold primitive bodies of the outer solar system. This hyperspectral thermal imager would serve as a significant advancement over standard thermal imagers and would complement information gathered from other spectrometers that function at shorter wavelengths. The bolometers are fabricated out of the high temperature superconductor YBCO, which is patterned to form kinetic inductance devices (KIDs) and suspended on thin membranes so that they function as bolometers. These devices are multiplexed using microwave readout to achieve arrays of thousands of bolometers. The superconducting bolometers operate at 50 K to offer much higher sensitivity compared to standard radiometers operating at 300 K, but they do not require the complex, expensive coolers that are necessary for detectors made of low temperature superconductors.