Developed by a team of physicists from the University of Bonn and the University of Bristol, this new method makes it possible to precisely determine the position of atoms in 3D in a single image and is based on an original physical principle.
The different directions of rotation of the various “dumbbells” indicate that the atoms are in different planes. Image credit: Institute of Applied Physics, University of Bonn.
“If you have ever used a microscope to study plant cells in your biology class, you can probably recall a similar situation,” said Tanguy Legrand and colleagues at the University of Bonn.
“It's easy to see that a particular chloroplast is located above and to the right of the nucleus. But are they both on the same plane?”
“However, when we adjust the focus of the microscope, we find that the images of the nuclei become clearer, while the images of the chloroplasts become blurred.”
“One of them has to be a little higher than the other, and the other a little lower than the other. However, this method doesn't give you exact details about the vertical position.”
“The principle is very similar if you want to observe individual atoms rather than cells. So-called quantum gas microscopes can be used for this purpose.”
“This allows us to directly determine the x and y coordinates of atoms.”
“However, it is much more difficult to measure its z-coordinate, and thus its distance to the objective lens. To find out in which plane an atom lies, we need to take multiple images by moving the focus to various different planes. I need to take a picture of a plane. This is a complex and time-consuming process. ”
“We have developed a method that completes this process in one step,” Dr. Legrand said.
“To achieve this, we use an effect that was already known in theory since the 1990s but had not yet been used in quantum gas microscopy.”
To experiment with atoms, you must first cool them down significantly until they barely move.
It is then possible to confine them to a standing wave of laser light, for example.
The egg then slides into the trough of the waves so that it fits inside the egg box.
After being captured, it is exposed to an additional laser beam and stimulated to emit light to reveal its location.
The resulting fluorescence appears as slightly blurred round spots in quantum gas microscopy.
“We have now developed a special method to transform the wavefront of light emitted by atoms,” said Dr. Andrea Alberti, also from the University of Bonn.
“Instead of a typical round spot, the deformed wavefront produces a dumbbell shape on the camera, which rotates itself.”
“The direction this dumbbell points is determined by the distance light travels from the atom to the camera.”
Professor Dieter Meschede from the University of Bonn said: “The dumbbell acts like a compass needle, and depending on its direction we can read the Z coordinate.”
This new method could be used to develop new quantum materials with special properties.
“For example, we can find out what quantum mechanical effects occur when atoms are arranged in a particular order,” said physicist Dr Carrie Widener from the University of Bristol.
“This allows us to simulate the properties of three-dimensional materials to some extent without having to synthesize them.”
team's work It was published in the magazine Physical review A.
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Tanguy Legrand other. 2024. His three-dimensional imaging of single atoms in optical lattices by helical point spread function engineering. Physics. Rev.A 109 (3): 033304; doi: 10.1103/PhysRevA.109.033304
Source: www.sci.news
