Summary
A superconducting quantum interference device (SQUID) is an extremely sensitive magnetic field detector. Microstrip SQUIDs can amplify weak radio frequency (RF) signals, a capability that makes them attractive as a potential alternative to the cryogenic semiconductor-based RF amplifiers that are available commercially, but at a cost of approximately $6,000 each. The challenge of using microstrip SQUIDs has been that they are static sensitive and can be overwhelmed by external noise. By tweaking microstrip SQUID design to achieve the quantum noise limit, and by packaging the technology into a more practical configuration, our team is working to reduce the cost of the SQUID approach by an order of magnitude. We also are working toward a much higher performance amplifier, with voltage noise reduced ten fold.
In the course of our work, we expect to fabricate “user-friendly” SQUIDs – packaging the RF filtering, RF-SQUID, and amplification together – such that a non-specialist could easily run the amplifier with the ease of running a conventional semiconductor amplifier. In addition to producing a practical, high-performance and economical amplifier, we believe that our work will facilitate multiple new quantum readout applications, as well as interesting fundamental physics.
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