Planar antenna-coupled transition-edge hot electron microbolometer

We describe a new type of bolometric detector for millimeter and submillimeter wavelengths. The detector is a variant of the Transition Edge Sensor (TES), which has recently been used to build bolometers. In this version of the TES, we couple radiation from a planar antenna to an absorbing normal metal film which is electrically connected to a superconducting thin film. The lateral dimensions of the absorber and TES are ~10 microns. At low temperatures, the thermal isolation between the electrons and the lattice in the absorber and the superconductor allows the electrons to heat up. We call this device a Transition-edge Hot-electron Microbolometer (THM). These detectors could have numerous advantages for lowbackground measurements in the far-IR, such as, background-limited sensitivity, short time constant, wide spectral range, immunity to cosmic rays, low microphonic noise and simple readout electronics. We are currently building a low-frequency scale model of the planar antenna to characterize microwave properties of the system.