ABSTRACT Electromagnetically induced transparency allows light transmission through dense atomic media by means of quantum interference1. Media with electromagnetically induced transparency

have very interesting properties, such as extremely slow group velocities2,3,4. Quasiparticles, the so-called dark polaritons, which are mixtures of a photonic and an atomic contribution5,

are associated with slow light propagation. Here, we demonstrate that these excitations behave as particles with a non-zero magnetic moment, which is in clear contrast to the properties of a

free photon. It is found that light passing through a rubidium gas cell, under the conditions of electromagnetically induced transparency, is deflected by a small magnetic field gradient.

subscription content, access via your institution ACCESS OPTIONS Access through your institution Subscribe to this journal Receive 12 print issues and online access $259.00 per year only

$21.58 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout

ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS PHOTOELECTRIC EFFECT WITH A

TWIST Article 10 August 2020 NONLINEAR-OPTICAL QUANTUM CONTROL OF FREE-ELECTRON MATTER WAVES Article 12 June 2023 RESONANT PHASE-MATCHING BETWEEN A LIGHT WAVE AND A FREE-ELECTRON

WAVEFUNCTION Article 12 October 2020 REFERENCES * Arimondo, E. Coherent population trapping in laser spectroscopy. _Prog. Opt._ 35, 257–354 (1996). Article  ADS  Google Scholar  * Hau, L.

V., Harris, S. E., Dutton, Z. & Behroozi, C. H. Light speed reduction to 17 metres per second in an ultracold atomic gas. _Nature_ 397, 594–598 (1999). Article  ADS  Google Scholar  *

Kash, M. et al. Ultraslow group velocity and enhanced nonlinear optical effects in a coherently driven hot atomic gas. _Phys. Rev. Lett._ 82, 5229–5232 (1999). Article  ADS  Google Scholar 

* Budker, D., Kimball, D. F., Rochester, S. M. & Yashchuk, V. V. Nonlinear magneto-optics and reduced group velocity of light in atomic vapor with slow ground state relaxation. _Phys.

Rev. Lett._ 83, 1767–1770 (1999). Article  ADS  Google Scholar  * Fleischhauer, M. & Lukin, M. D. Dark-state polaritons in electromagnetically induced transparency. _Phys. Rev. Lett._

84, 5094–5097 (2000). Article  ADS  Google Scholar  * Jackson, J. D. _Classical Electrodynamics_ (Wiley, New York, 1975). MATH  Google Scholar  * Ashcroft, N. W. & Mermin, N. D. _Solid

State Physics_ (Saunders College Publishing, New York, 1976). MATH  Google Scholar  * Scully, M. O. & Fleischhauer, M. High-sensitivity magnetometer based on index-enhanced media. _Phys.

Rev. Lett._ 69, 1360–1363 (1992). Article  ADS  Google Scholar  * Liu, C., Dutton, Z., Behroozi, C. H. & Hau, L. V. Observation of coherent optical information storage in an atomic

medium using halted light pulses. _Nature_ 409, 490–493 (2001). Article  ADS  Google Scholar  * Phillips, D. F., Fleischhauer, A., Mair, A., Walsworth, R. L. & Lukin, M. D. Storage of

light in atomic vapor. _Phys. Rev. Lett._ 86, 783–786 (2001). Article  ADS  Google Scholar  * Schlesser, R. & Weis, A. Light-beam deflection by cesium vapor in a transverse-magnetic

field. _Opt. Lett._ 17, 1015–1017 (1992). Article  ADS  Google Scholar  * Holzner, R. et al. Observation of magnetic-field-induced laser beam deflection in sodium vapor. _Phys. Rev. Lett._

78, 3451–3454 (1997). Article  ADS  Google Scholar  * Purves, G. T., Jundt, G., Adams, C. S. & Hughes, I. G. Refractive index measurements by probe-beam deflection. _Eur. Phys. J. D_ 29,

433–436 (2004). Article  ADS  Google Scholar  * Moseley, R. R., Shepherd, S., Fulton, D. J., Sinclair, B. D. & Dunn, M. H. Spatial consequences of electromagnetically induced

transparency: observation of electromagnetically induced focusing. _Phys. Rev. Lett._ 74, 670–673 (1995). Article  ADS  Google Scholar  * Campbell, G. K. et al. Photon recoil momentum in

dispersive media. _Phys. Rev. Lett._ 94, 170403 (2005). Article  ADS  Google Scholar  * Lukin, M. D., Yelin, S. F. & Fleischhauer, M. Entanglement of atomic ensembles by trapping

correlated photon states. _Phys. Rev. Lett._ 84, 4232–4235 (2000). Article  ADS  Google Scholar  * Chanelière, T. et al. Storage and retrieval of single photons transmitted between remote

quantum memories. _Nature_ 438, 833–836 (2005). Article  ADS  Google Scholar  * Eisaman, M. D. et al. Electromagnetically induced transparency with tunable single-photon pulses. _Nature_

438, 837–841 (2005). Article  ADS  Google Scholar  * Aharonov, Y. & Casher, A. Topological quantum effects for neutral particles. _Phys. Rev. Lett._ 53, 319–321 (1984). Article  ADS 

MathSciNet  Google Scholar  * Leonhardt, U. & Piwnicki, P. Relativistic effects of light in moving media with extremely low group velocity. _Phys. Rev. Lett._ 84, 822–825 (2000). Article

  ADS  Google Scholar  * Bolkart, C., Rostohar, D. & Weitz, M. Dark resonances with variable Doppler sensitivity. _Phys. Rev. A_ 71, 043816 (2005). Article  ADS  Google Scholar  *

Fleischhauer, M. & Lukin, M. D. Quantum memory for photons: Dark-state polaritons. _Phys. Rev. A_ 65, 022314 (2002). Article  ADS  Google Scholar  Download references ACKNOWLEDGEMENTS We

are indebted to M. Fleischhauer for his direct calculation of the magnetic dipole moment from the dark-polariton model and for discussions. M.W. acknowledges hospitality by the CUA during

his guest stay at MIT. We acknowledge financial support from the Deutsche Forschungsgemeinschaft, the Landesstiftung Baden-Württemberg and the European Community. AUTHOR INFORMATION AUTHORS

AND AFFILIATIONS * Physikalisches Institut der Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen, Germany Leon Karpa & Martin Weitz * Center of Ultracold Atoms, Massachusetts

Institute of Technology, Cambridge, Massachusetts 02139, USA Martin Weitz * Institut für Angewandte Physik, Wegelerstr. 8, 53115 Bonn, Germany Martin Weitz Authors * Leon Karpa View author

publications You can also search for this author inPubMed Google Scholar * Martin Weitz View author publications You can also search for this author inPubMed Google Scholar CORRESPONDING

AUTHOR Correspondence to Martin Weitz. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION:

SUPPLEMENTARY FIGURES S1, S2 AND SUPPLEMENTARY TABLE 1 (PDF 121 KB) RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Karpa, L., Weitz, M. A Stern–Gerlach

experiment for slow light. _Nature Phys_ 2, 332–335 (2006). https://doi.org/10.1038/nphys284 Download citation * Received: 19 January 2006 * Accepted: 22 March 2006 * Published: 16 April

2006 * Issue Date: May 2006 * DOI: https://doi.org/10.1038/nphys284 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a

shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative