Abstract
Fundamental optics such as lenses and prisms work by applying phase shifts of several radians to incoming light, and rapid control of such phase shifts is crucial to telecommunications. However, large, controllable optical phase shifts have remained elusive for isolated quantum systems. We have used a single trapped atomic ion to induce and measure a large optical phase shift of radians in light scattered by the atom. Spatial interferometry between the scattered light and unscattered illumination light enables us to isolate the phase shift in the scattered component. The phase shift achieves the maximum value allowed by atomic theory over the accessible range of laser frequencies, pointing out new opportunities in microscopy and nanophotonics. Single-atom phase shifts of this magnitude open up new quantum information protocols, in particular long-range quantum phase-shift-keying cryptography.
- Received 14 September 2012
DOI:https://doi.org/10.1103/PhysRevLett.110.113605
© 2013 American Physical Society
Synopsis
Big Shifts on an Atomic Scale
Published 14 March 2013
Laser light scattered from a single atom undergoes large optical phase shifts that may be useful in imaging and quantum information transmission.
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