Amplifying The Cosmos And Quantum World.
If you thought you had a great home stereo system, then move over. Researchers at Caltech and NASA’s Jet Propulsion Laboratory (JPL) have recently finished something amazing.
It’s work on a new style of amplifier which boosts electric signals. Now everything from studying stars, galaxies and black holes takes on a new twist. Not only will we gain new insights on old subjects – but we’ll be reaching further into the quantum world and developing quantum computers. “This amplifier will redefine what it is possible to measure,” says Jonas Zmuidzinas, Caltech’s Merle Kingsley Professor of Physics, the chief technologist at JPL, and a member of the research team.
To clarify, most amplifiers are a simple tool which magnifies the strength of a weak signal. “Amplifiers play a basic role in a wide range of scientific measurements and in electronics in general,” says Peter Day, a visiting associate in physics at Caltech and a principal scientist at JPL. “For many tasks, current amplifiers are good enough. But for the most demanding applications, the shortcomings of the available technologies limit us.”
Almost all of us are familiar with a conventional transistor amplifier. They are similar to those which power your car or house stereo speakers. This ordinary equipment works on a broad range of frequencies and are also capable of boosting signals from the very faint to the very strong. This is known as “dynamic range” and it enables your speakers to work with both the loud and quiet parts of a song. However, when dealing with an extremely faint signal – such as that produced by a very distant galaxy – a transistor introduces “noise”. This creates a stronger, more powerful signal, but it just isn’t a clear sound.
As an alternative, a parametric amplifier is incredibly sensitive. It boosts a weak signal by utilizing a stronger one known as a “pump signal”. As both pass through this form of amplifier, the pump adds energy to the weaker signal and amplifies it. Around five decades ago, Amnon Yariv, Caltech’s Martin and Eileen Summerfield Professor of Applied Physics and Electrical Engineering, demonstrated the parametric amplifier as a low noise alternative – its only noise produced by the movement of atoms and waves according to the laws of quantum mechanics. However, it did have a drawback… it could only amplify a very narrow frequency range and possessed a poor dynamic range.
Now enter the researchers at JPL and Caltech…Their new amplifier is a form of the standard parametric and combines the best features of other amplifiers. It covers a frequency range ten times wider than similar sensitive models. It also amplifies strong signals without distorting them and produces the lowest amount of naturally occurring noise. Versions of the amplifier can be designed to work at frequencies ranging from a few gigahertz to a terahertz (1,000 GHz). To put that into perspective, a gigahertz is about ten times stronger than a commercial FM radio signal! “Our new amplifier has it all,” Zmuidzinas says. “You get to have your cake and eat it too.”
Just what is the secret behind the new parametric amplifier? Try superconductors – a material which allows electric current to flow a zero resistance when lowered to a certain temperature. In this new form of amplifier, researchers employ titanium nitride (TiN) and niobium titanium nitride (NbTiN). These two elements have the correct properties to allow the pump signal to amplify the weak one. Although this new design has huge potential applications, the reason it was built was to help study the Universe by boosting microwave signals. However, astronomers can also utilize it in other ways, such as amplifying everything from radio waves to X-rays.
This new instrument can boost radio signals from faint sources such as distant galaxies, black holes and other exotic comic objects. Amplifying signals in millimeter to submillimeter wavelengths (between radio and infrared) will allow astronomers to study the cosmic microwave background. Other applications include peering behind the veil of dusty galaxies to witness starbirth – or to probe primeval galaxies.
According to the news release, the team has already begun working to produce such devices for Caltech’s Owens Valley Radio Observatory (OVRO) near Bishop, California, about 250 miles north of Los Angeles. These amplifiers, Zmuidzinas says, could be incorporated into telescope arrays like the Combined Array for Research in Millimeter-wave Astronomy at OVRO, of which Caltech is a consortium member, and the Atacama Large Millimeter/submillimeter Array in Chile.
The really interesting fact is that it isn’t necessary to directly amplify an astronomical signal… this new technology can be used to ramp up an electronic signal from a light source, such as optical, ultraviolet, or even X-ray. This will add a new dimension to existing telescopes, allowing researchers to uncover even more details in faint objects.
Thanks to low noise and extreme sensitivity, this new instrument can also be used to explore the quantum world. According to Keith Schwab, a professor of applied physics at Caltech, he can use the amplifier to measure the behavior of tiny mechanical devices that operate at the boundary between classical physics and the strange world of quantum mechanics.
The amplifier could also be used in the development quantum computers – which are still beyond our technological reach but should be able to solve some of science’s hardest problems much more quickly than any regular computer.
“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,” Zmuidzinas says. And by creating their new device, the researchers have shown that it is indeed possible to build an essentially perfect amplifier. “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.”
So the next time the kid down the street drives by – giving off bass tones loud enough to vibrate your windows – just smile. With this new technology, astronomers could produce a signal from a pulsar that would strip the paint off his car!
Original Story Source: Caltech News Release.