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JILA Team Demonstrates 'A New Way of Lasing': A 'Superradiant' Laser Video Transcript

Visual: Research James Thompson in a laboratory.

“My name is James Thompson. I am a NIST physicist here are JILA at the University of Colorado. And this is my cold atom lab where we actually laser cool and trap atoms and we do interesting things in the quantum world.

So we’ve developed something called a superradiant laser that operates in this really strange regime that’s interesting from a physics perspective, which is it operates with very few photons around to drive the stimulation process that you’d normally associate with lasers. But in addition, it’s very interesting from a technology perspective, because we show that the color of light that’s emitted by this laser is very insensitive to the environmental shaking of things you put around the laser. “

Visual: Thompson holds his hands out and red particles appear to bounce around between them.

“And that actually turns out to one of the chief problems for making the best lasers we can here at NIST and a few other places in the world.

So in our laser we actually trap about 1 million atoms of rubidium in between two mirrors.

Visual: Atoms are shown glowing in a vacuum chamber.

“And we levitate them there. And then those atoms, while they’re sitting between the mirrors, they spontaneously synchronize with each other.

This is kind of like crickets. They all could chirp independently but after a while they hear each other, and they start chirping together.

Visual: Cartoon crickets are shown.

So these atoms synchronize, and they start actually emitting light together, and they emit it, what we call “in phase.” And that’s like the crickets chirping together. And so they begin to emit in phase with each other, and that leads to a huge enhancement in a huge amount of light we get out. We call that enhancement stimulation.

In a normal laser, you build up many, many quanta of light, called photons, bouncing in between the mirrors.

Visual: Thompson holds out his hands and rings of laser light bounce at regular intervals between them.

And they’re the things that actually carry the information, that actually make this laser tick like a clock in a very regular fashion. In fact, in a normal laser you have millions and millions and millions of these quanta of light bouncing around.

In our laser we actually are able to operate and see that it behaves just like a laser with less than one photon in the cavity. Visual: A single beam of light flashes from Thompson’s right hand to his left.

In fact we can operate with as few as one fifth of a photon on average inside the cavity. And that means that sometimes if you were to look between those mirrors you would even find that there is no light inside the cavity. There are no photons.

Visual: Thompson holds out his hands and no light appears between them.

And so that’s a really strange regime for a laser to operate in. It is very novel. And we think in and of itself that’s really interesting and neat to do.

And we want really precise colors. Why? Why do we want precise colors? Well, because you can think of light as like a pendulum. It’s a ticking object. And we actually use it to make very, very precise atomic clocks at NIST and here at JILA. In addition, you can also think of it spatially, when you can take that light and you actually launch it and allow it to propagate in space, it becomes a kind of ruler and it allows you to measure distances very precisely. So using some of the concepts we’ve demonstrated in our set up, in the future you might be able to make much, much more single-color lasers and be able to use those to make very much more precise measurements, and better atomic clocks for things like the global positioning system that we use in our cars every day.

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