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Caltech Researchers Build Superconductor Parametric Amplifier

Researchers at Caltech have developed a new type of amplifier that has very low noise while operating over a wide frequency range. Highly sensitive parametric amplifiers, which boost a weak input signal using a strong signal called the pump signal, have been used in radio astronomy and quantum physics since being developed about 50 years ago by Amnon Yariv at Caltech. 

The new amplifier builds on Yariv's design, but incorporates the superconducting materials titanium nitride and niobium titanium nitride which allow current to flow with zero resistance when they are sufficiently cooled. 

The new amplifier avoids one of the problems with the original parametric amplifiers--narrow bandwidth. The superconducting parametric amplifier can be designed to work at frequencies ranging from a few gigahertz up to a terahertz (1,000 GHz). 

“This amplifier will redefine what it is possible to measure,” said Jonas Emuidzinas, Caltech's Merle Kingsley professor of physics, and the chief technologist at JPL, and a member of the research team. “Our new amplifier has it all. You get to have your cake and eat it too.”

The device was built primarily to study the universe at microwave frequencies, but it can also be used to build amplifiers that help astronomers observe wavelengths ranging from radio waves to X-rays. 

“It's hard to predict what all of the applications are going to end up being, but a nearly perfect amplifier is a pretty handy thing to have in your bag of tricks,” said Emuidzinas. Our instrument still has a few rough edges that need polishing before we would call it perfect, but we think our results so far show that we can get there.”