Synopsis: Laser Suppression of Noise

In laser metrology, adding additional laser pulses, separated in time from the first, suppresses energy line shifts and allows for even more precision.
Synopsis figure
N. Huntemann et al., Phys. Rev. Lett. (2012)

Spectral purity makes the laser the tool of choice for precise analysis of the internal structure of atoms and molecules, but its intensity may shift the very energy levels under study, which limits metrology applications. In a paper in Physical Review Letters, Nils Huntemann at Physikalisch-Technische Bundesanstalt in Braunschweig, Germany, and colleagues report on a way to suppress these energy level shifts.

The authors build upon a precision spectroscopy technique developed by Norman Ramsey in the 1950s for nuclear magnetic resonance, which has become very important for atomic clocks and quantum information processing. In this scheme, one electromagnetic field prepares a quantum system, while a second spatially separated field interrogates the system after it evolves for a time. This method greatly reduces the perturbations of the energy states by the probing fields. Huntemann et al. replace the two separated fields with laser pulses separated in time, which, according to theory, eliminates the level shifts and reduces the sensitivity to laser intensity fluctuations. As a test case, they applied the method to a strongly forbidden electronic transition in a single trapped ytterbium-171 ion that would typically require high intensity to study, because of its low transition rate.

With this technique, which the authors call “hyper-Ramsey spectroscopy,” they were able to suppress the laser-induced line shift by four orders of magnitude. The hope is to eventually apply this approach to atomic clocks, time and frequency standards, and quantum information processing, where high stability and long coherence times are necessary. – David Voss


Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsOptics

Previous Synopsis

Soft Matter

The Blueprint for DNA Origami

Read More »

Next Synopsis

Atomic and Molecular Physics

Cooling Neutral Atoms in Optical Tweezers

Read More »

Related Articles

Synopsis: Terahertz Combs Get Fine Teeth
Optics

Synopsis: Terahertz Combs Get Fine Teeth

A new scheme to generate terahertz frequency combs features unprecedented bandwidth and frequency accuracy. Read More »

Synopsis: Rapid Alignment
Atomic and Molecular Physics

Synopsis: Rapid Alignment

A frequency comb can align an ensemble of molecules 150 million times per second. Read More »

Viewpoint: Negative Ions in Cold Storage
Atomic and Molecular Physics

Viewpoint: Negative Ions in Cold Storage

A cooled ring stores high-speed negative ions for more than 1000 seconds and enables new studies of atomic and molecular ions that are important in interstellar and atmospheric chemistry. Read More »

More Articles