Planar Frequency Selective Bolometric Array at 350 GHz

Journal article, 2014

In this paper we describe a bolometric focal plane array consisting of the Cold Electron Bolometer integrated in a Frequency Selective Surface fabricated on a Silicon substrate with a backshort. This array is formed by a periodic pattern of conducting annular square and ring shapes and the two-terminal CEB is embedded directly in the element. The CEBs impedance has been matched to the FSS which provides resonant interaction with incident sub-millimetre radiation. A further degree of freedom for the tuning is via varying the thickness of the substrate. We've been able to design the FSS at 350 GHz with peak coupling of more than 90% as is common for FSS based filters. A prototype of such a detector has been fabricated and optical response to blackbody radiation has been measured, indicating responsivities of 2*10^9 V/W and higher at 185 mK and 3*10^8 V/W and higher at 300 mK. The details of this new concept, together with numerical simulations and optical measurements are presented.