Novel ion trap with optical fiber could link atoms and light in quantum networks

Jul 08, 2010
This is a diagram of a NIST ion trap that incorporates an optical fiber to collect light emitted by the ions (electrically charged atoms). Individual electrodes used to trap an ion 30 to 50 micrometers above the surface are shown in different colors surrounding a 50-micrometer-wide hole where light is collected and deposited in a fiber attached below. Credit: A. VanDevender/NIST

Physicists at the National Institute of Standards and Technology have demonstrated an ion trap with a built-in optical fiber that collects light emitted by single ions (electrically charged atoms), allowing quantum information stored in the ions to be measured. The advance could simplify quantum computer design and serve as a step toward swapping information between matter and light in future quantum networks.

Described in a forthcoming issue of ,* the new device is a 1-millimeter-square ion trap with a built-in optical fiber. The authors use ions as quantum bits (qubits) to store information in experimental , which may someday solve certain problems that are intractable today. An ion can be adjustably positioned 80 to 100 micrometers from an , which detects the ion's fluorescence signals indicating the qubit's information content.

"The design is helpful because of the tight coupling between the ion and the fiber, and also because it's small, so you can get a lot of fibers on a chip," says first author Aaron VanDevender, a NIST postdoctoral researcher.

NIST scientists demonstrated the new device using magnesium ions. Light emitted by an ion passes through a hole in an electrode and is collected in the fiber below the electrode surface (see image). By contrast, conventional ion traps use large external lenses typically located 5 centimeters away from the ions—about 500 times farther than the fiber—to collect the fluorescence light. Optical fibers may handle large numbers of ions more easily than the bulky optical systems, because multiple fibers may eventually be attached to a single .

The fiber method currently captures less light than the but is adequate for detecting because ions are extremely bright, producing millions of photons (individual particles of light) per second, VanDevender says. The authors expect to boost efficiency by shaping the fiber tip and using anti-reflection coating on surfaces. The new trap design is intended as a prototype for eventually pairing single ions with single photons, to make an interface enabling matter qubits to swap information with photon qubits in a quantum computing and communications network.

Photons are used as qubits in quantum communications, the most secure method known for ensuring the privacy of a communications channel. In a quantum network, the information encoded in the "spins" of individual could be transferred to, for example, electric field orientations of individual photons for transport to other processing regions of the network.

Explore further: Physicists design zero-friction quantum engine

More information: *A.P. VanDevender, Y. Colombe, J. Amini, D. Leibfried and D.J. Wineland. Efficient fiber optic detection of trapped ion fluorescence. Physical Review Letters. Forthcoming.

Related Stories

Physicists Demonstrate Quantum Memory with Matter Qubits

Jul 03, 2009

(PhysOrg.com) -- For the first time, scientists have successfully operated a quantum gate between two remote particles of matter, marking an important step toward the development of a quantum computer. In ...

Ion trap quantum computing

May 12, 2009

(PhysOrg.com) -- “Right now, classical computers are faster than quantum computers,” René Stock tells PhysOrg.com. “The goal of quantum computing is to eventually speed up the time scale of solving certain import ...

Sustained quantum information processing demonstrated

Aug 06, 2009

Raising prospects for building a practical quantum computer, physicists at the National Institute of Standards and Technology have demonstrated sustained, reliable information processing operations on electrically ...

Recommended for you

Physicists design zero-friction quantum engine

Sep 16, 2014

(Phys.org) —In real physical processes, some energy is always lost any time work is produced. The lost energy almost always occurs due to friction, especially in processes that involve mechanical motion. ...

Fluid mechanics suggests alternative to quantum orthodoxy

Sep 12, 2014

The central mystery of quantum mechanics is that small chunks of matter sometimes seem to behave like particles, sometimes like waves. For most of the past century, the prevailing explanation of this conundrum ...

The sound of an atom has been captured

Sep 11, 2014

Researchers at Chalmers University of Technology are first to show the use of sound to communicate with an artificial atom. They can thereby demonstrate phenomena from quantum physics with sound taking on ...

The quantum revolution is a step closer

Sep 11, 2014

A new way to run a quantum algorithm using much simpler methods than previously thought has been discovered by a team of researchers at the University of Bristol. These findings could dramatically bring ...

User comments : 0