This camera can snap atoms better than a smartphone
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In suburban Chicago, about 54 miles west of Lake Michigan, there is a hole about 330 feet deep in the ground. Long ago, scientists drilled shafts for particle physics experiments that have long disappeared from this world. Now, in a few years, they plan to reuse that shaft for a new project with his mysteriously named MAGIS-100.
Once MAGIS-100 is complete, physicists plan to use it to detect hidden treasures: dark matter, the mysterious invisible Something It is believed to occupy most of the universe. and gravitational waves, ripples in space-time caused by cosmic impacts such as black hole collisions. They hope to find signatures of the elusive phenomenon by observing the quantum signatures left in raindrop-sized clouds of strontium atoms.
However, actually observing these atoms is more difficult than expected. To successfully conduct similar experiments, physicists have so far relied on cameras that rival smartphone cameras. While this technique might work fine for sunsets and appetizing shots of food, there are limits to what physicists can see at the atomic level.
[Related: It’s pretty hard to measure nothing, but these engineers are getting close]
Fortunately, some physicists may be doing an upgrade. Research teams from various groups in Stanford, California have created a unique camera contraption that relies on a dome of mirrors. The extra reflections help you see what light is entering the lens and tell you what angle a particular patch of light is coming from. I hope to be able to.
Cell phone cameras and DSLRs don’t care where the light travels from. Capture the color reflected by photon intensity and wavelength. If you want family, city, or Grand Canyon photos, that’s it. But for studying atoms it is not desirable. “You’re throwing out a lot of light,” says her Murtaza Safdari, a physics graduate student at Stanford University and one of her creators.
Physicists want to store that information so that they can draw more complex 3D images of the object (or objects) under study. And when it comes to the detailed analysis that physicists like to do, the more information you can get at once, the faster and better.
One way to get that information is to set up multiple cameras so that you can take pictures from multiple angles and stitch them together for a more detailed view. This works well with say 5 cameras. But some physics experiments require very precise measurements, so even 1,000 cameras may not work.
So, in the Stanford basement, researchers decided to create their own system to get around this problem. “Our idea was … basically, can we fully capture as much information as possible, or can we retain directional information,” says Safdari.
The finished prototype, made from off-the-shelf 3D printed components, looks like a shallow dome with tiny mirror-like dots scattered inside. The pattern appears to form a pleasing optical illusion of concentric circles, carefully calculated to maximize the amount of light hitting the camera.
In the MAGIS-100 project, the cloud of strontium atoms to be shot falls within the dome. A short flash of light from an external laser beam scatters off the mirror dot and passes through clouds at myriad angles. The lens picks up the resulting reflections, how they interacted with the molecules and which dots bounced off.
Then, from that information, a machine learning algorithm can reconstruct the cloud’s 3D structure. Currently this rebuild takes a few seconds. In an ideal world, it would take a few milliseconds or less. But like the algorithms used to adapt self-driving cars to the world around them, researchers believe computer code will perform better.
The creators haven’t tested the camera on the atom yet, but they scanned a sample part of the right size to try it out. I was able to find flaws where the letters differed from the intended design.
For atomic experiments like the MAGIS-100, this instrument stands apart from others on the market. Ariel Schwartzman, a physicist at his SLAC National Accelerator Laboratory in California and co-creator of the setup at Stanford University, said: They scoured catalogs of photographic equipment for one that would allow them to view the atomic cloud from multiple angles at once. “Nothing was available,” Schwartzman says.
Complicating matters, many experiments require atoms to be at rest at cryogenic temperatures just above absolute zero. This means that low light conditions are required. A bright light source for too long can heat up quickly. Setting the camera to a longer exposure time helps, but it also means sacrificing some of the detail and information you want in the final image. “You’re diffusing the atomic cloud,” says her Sanha Cheong, a physics graduate student at Stanford University and a member of the camera manufacturing crew. Mirror domes, on the other hand, are intended to use only short laser flashes with microsecond exposures.
[Related: Stanford researchers want to give digital cameras better depth perception]
The author’s next challenge is to actually place the camera on the MAGIS-100. This requires a lot of adjustments to fit the camera to the much larger shaft and vacuum. But physicists have hope. Such cameras may go far beyond detecting obscure effects around atoms. I plan to use it for all sorts of purposes.
“Being able to capture as much light and information in one shot with the shortest possible exposure opens new doors,” says Cheong.
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