Imaging of single infrared, optical, and ultraviolet photons using distributed tunnel junction readout on superconducting absorbers

Single-photon imaging spectrometers of high quantum efficiency in the infrared to ultraviolet wavelength range, with good timing resolution and with a vanishing dark count rate, are on top of the wish list in earth-bound astronomy, material and medical sciences, or quantum information technologies. We review and present improved operation of a cryogenic detector system potentially offering all these qualities. It is based on a superconducting absorber strip read out with superconducting tunnel junctions. The detector performance is discussed in terms of responsivity, noise properties, and energy and position resolutions. Dynamic processes involved in the signal creation and detection are investigated for a basic understanding of the physics and for possible application-specific modifications of device characteristics.