Superconducting metamaterial for sub-millimeter wave imaging: First light

We present results of first experiments with elementary cells for detection of sub-millimeter-wave radiation. The cells realize frequency-division multiplexing (FDM) readout of an antenna coupled superconducting hot electron bolometers (HEB) by means of integrated GHz-range superconducting resonators. Such cells can be coupled to a single transmission line for FDM readout, forming a large format imaging metasurface. The design of metasurface, consisting of hexagonal clusters, is discussed and experimental results for both the single cell and the 7-element hexagonal cluster are presented. The prototypes have been fabricated using thin film Nb technology with T_C of HEB bridges about 5 K and frequencies of resonators in 5-8 GHz range. Optical sensitivity measurements using a black body radiation source resulted in optical NEP of the cell about 3×10^-14 W/√Hz at ambient temperature 1.4 K.