Design analysis of a novel low temperature bolometer

Abstract

The authors propose a novel antenna-coupled superconducting bolometer which makes use of the thermal boundary resistance available at low temperatures. The radiation is collected by a planar self-complementary antenna and thermalized in a small thin-film resistor. The resulting temperature rise is detected by a transition edge thermometer which can be (but need not be) a separate film. All components are deposited directly on substrate so that arrays can be conveniently produced by conventional lithographic techniques. The active area of the bolometer is thermally decoupled by its small size and by the thermal resistance of the boundaries with the substrate and the antenna terminals. Design calculations based on a 2- mu m*2- mu m film of a superconductor with T/sub c/ approximately=0.1 K give an NEP approximately=10/sup -18/ WHz/sup -1/2/, a time constant approximately=10/sup -6/ s, and responsivities up to approximately=10/sup 9/ V/W. These specifications meet the requirements for NASA's Space Infrared Telescope Facility and Sub-Millimeter Moderate Mission. Useful applications also exist at /sup 3/He and /sup 4/He temperatures. The calculated NEP scales as T/sup 5/2/. Materials, architectures, and readout schemes are discussed.