On-Chip Integrated SQUID Readout for Superconducting Bolometers

Abstract

We present the first steps toward a 288 pixel sub-millimeter wavelength bolometer camera. We have used bolometers of the transition edge type, choosing a thermometer made of a proximity bilayer of Mo and the alloy Au/Pd with a designed transition temperature of about 500 mK. We have adapted our well-developed niobium based technology for SQUID manufacturing in order to be able to fabricate the current sensor and the bolometer on a common substrate. The function of both devices was successfully tested at the operating temperature of 300 mK.

Disorder control ofTCin thin film Mo

“…An understanding of the T C dependence on the sputtering parameters is useful from at least a practical point of view, especially if the superconductor is used in a metalsuperconductor bilayer where a reproducible T C is needed [23]. Therefore, we have looked at this dependence with a view to improving the stability of our Mo/AuPd bilayers [23][24][25]. Additionally, we have looked at possible influences from the preceding deposition in the chamber and the pre-cleaning conditions.…”

Measurements of dichroic bow-tie antenna arrays with integrated cold-electron bolometers using YBCO oscillators

“…Current–voltage ( I – V ) characteristics ( Figure 5 ), frequency response ( Figure 6 ), and noise at various bias currents ( Figure 7 ) were measured. While the samples were designed to be used in the voltage bias mode with a SQUID readout system similar to the one described in [ 10 ], they were measured in the current bias mode with AD745 operational amplifiers due to the absence of proper equipment in our lab. Hence, the results might be different from the expected values.…”

“…The main channel has 162 detectors, and each of the auxiliary channels has 82 detectors. It is intended to use SQUID readout [ 9 – 10 ] with frequency multiplexing for this mission [ 8 ]. The estimated photon noise equivalent power (NEP) for the auxiliary channels is about 2 × 10 −16 W/√Hz.…”

Examples of superconducting technology application: Sensing and interfacing

“…The low-temperature platform consists of a sensor array and a multiplexer circuitry. In the best case both parts are on-chip [11]. Digital circuits at room temperature (interface, FPGA, A/D and D/A converters, filters, clock timers) act as interface between the superconducting circuits and a computer, needed for controlling, signal processing, visualization, data storage and human interfacing.…”