NIST researchers develop miniature lens to sequester atoms

It’s notoriously troublesome to regulate atoms. They’re zigzagging like fireflies, sprouting from the strongest of containers and vibrating even at temperatures near absolute zero.

Nonetheless, scientists have to search out and manipulate single atoms for quantum gadgets, corresponding to atomic clocks or quantum computer systems, to perform correctly. If particular person atoms will be grouped and managed into giant matrices, they will act as quantum bits, or qubits – discrete small items of data whose state or route can finally be used to carry out calculations at speeds a lot larger than the quickest supercomputer.

Researchers on the Nationwide Institute of Requirements and Know-how (NIST), together with collaborators from JILA – a joint institute between the College of Colorado and NIST at Boulder – have proven for the primary time that they will hunt single atoms utilizing a brand new miniature model of “optical tweezers” – a system that catches atoms. Utilizing the laser beam as consuming sticks.


Illustration of centered gentle utilizing a flat glass floor studded with thousands and thousands of nanotubes (known as metallic) forming optical tweezers. (a) The cross-section of the machine depicts airplane gentle waves which might be centered by secondary waves generated by nanobeams of various sizes. (b) The identical metallic is used to seize and {photograph} the only rubidium atoms.

attributed to him:

Sean Kelly/Nest

Optical tweezers, winner of the 2018 Nobel Prize in Physics, usually function large centimeter lenses or extra-vacuum microscopic targets that maintain particular person atoms. NIST and JILA have beforehand used this expertise with nice success to create an atomic clock.

Within the new design, as a substitute of typical lenses, the NIST crew used unconventional optics — a sq. glass wafer about 4 mm lengthy printed with thousands and thousands of pillars a number of hundred nanometers (billionths of a meter) excessive that collectively act as very small. lenses. These printed surfaces, dubbed metasurfaces, focus laser gentle to entice, manipulate, and picture particular person atoms inside a vapor. The metasurfaces can function within the vacuum the place the trapped cloud of atoms is, not like common optical tweezers.

The method contains a number of steps. First, incoming gentle of a very easy form, often called a airplane wave, strikes teams of tiny nanopillars. (Planar waves are like transferring parallel plates of sunshine which have a uniform wave entrance, or part, whose vibrations stay synchronized with one another and don’t diverge or converge as they journey.) Wavelets, every barely out of sync with its neighbor. Consequently, neighboring waves attain their peaks at barely totally different instances.

These waves mix, or “interfer” with one another, inflicting them to focus all their vitality in a selected place – the situation of the atom that will likely be trapped.

Relying on the angle at which the incoming planar gentle waves strike the nanopillars, the small waves are centered in barely totally different locations, permitting the optical system to entice a sequence of particular person atoms situated in barely totally different places from one another.

As a result of the miniature flat lenses can function inside a vacuum chamber and require no transferring elements, atoms will be trapped with out having to construct and manipulate a posh optical system, mentioned NIST researcher Amit Agrawal. Different researchers at NIST and JILA have beforehand used typical optical tweezers with nice success in designing atomic clocks.

Within the new examine, Agrawal and two different NIST scientists, Scott Papp and Wenqi Zhu, together with collaborators from JILA’s Cindy Regal Group, designed, manufactured and examined the surfactants and performed single-atom trapping experiments.

In a paper printed right this moment in Quantum PRX, the researchers reported that they individually trapped 9 single rubidium atoms. Agrawal mentioned the identical expertise, which has been scaled up utilizing a number of metasurfaces or one with a big subject of view, ought to have the ability to entice lots of of single atoms, and will routinely prepared the ground to trapping an array of atoms with a wafer-scale optical system. .

The system held the atoms in place for about 10 seconds, lengthy sufficient to check the quantum mechanical properties of particles and use them to retailer quantum data. (Quantum experiments run on time scales from ten millionths to 1 thousandth of a second.)

To show that they’d captured rubidium atoms, the researchers lit them with a separate gentle supply, inflicting them to shine. Then the piercing surfaces performed a second essential function. At first, they fashioned and centered the incoming gentle that trapped the rubidium atoms. Now the metasurfaces have captured and centered the fluorescent gentle emitted by these identical atoms, and the fluorescent radiation is redirected to the digicam so as to picture the atoms.

Superficial metasurfaces can do greater than confine single atoms. By focusing gentle with pinpoint precision, metasurfaces can coax particular person atoms into particular quantum states, designed for particular atom-trapping experiments.

For instance, polarized gentle directed by tiny lenses may cause an atom — the same quantum property of the Earth spinning on its axis — to spin to level in a selected route. These interactions between centered gentle and single atoms are helpful for a lot of sorts of atom-scale experiments and gadgets, together with future quantum computer systems.

Paper: T.-W. Hsu, W. Zhu, T. Thiele, M. O. Brown, S. B. Papp, A. Agrawal and CA Regal. Trapping a single atom within the optical forceps of the floor lens. Quantum PRX. Posted on-line August 1, 2022. DOI: 10.1103/PRXQuantum.3.030316.