Light detection is usually a destructive process, in that detectors annihilate photons and convert them into electrical signals, making it impossible to see a single photon twice. But this limitation is not fundamental—quantum non-demolition strategies1,2,3 permit repeated measurements of physically observable quantities, yielding identical results. For example, quantum non-demolition measurements of light intensity have been demonstrated4,5,6,7,8,9,10,11,12,13,14, suggesting possibilities for detecting weak forces and gravitational waves3. But such experiments, based on nonlinear optics, are sensitive only to macroscopic photon fluxes. The non-destructive measurement of a single photon requires an extremely strong matter–radiation coupling; this can be realized in cavity quantum electrodynamics15, where the strength of the interaction between an atom and a photon can overwhelm all dissipative couplings to the environment. Here we report a cavity quantum electrodynamics experiment in which we detect a single photon non-destructively. We use atomic interferometry to measure the phase shift in an atomic wavefunction, caused by a cycle of photon absorption and emission. Our method amounts to a restricted quantum non-demolition measurement which can be applied only to states containing one or zero photons. It may lead to quantum logic gates16 based on cavity quantum electrodynamics, and multi-atom entanglement17.
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Braginsky, V. B. & Vorontsov, Y. I. Quantum mechanical limitations in macroscopic experiments and modern experimental techniques. Usp. Fiz. Nauk. 114, 41–53 (1974) [Sov. Phys. Usp. 17, 644–650 (1975]).
Braginsky, V. B. & Khalili, F. Y. Quantum Measurement (ed. Thorne, K. S.) (Cambridge Univ. Press, (1992).
Caves, C. M., Thorne, K. S., Drever, R. W. P., Sandberg, V. D. & Zimmermann, M. On the measurement of a weak classical force coupled to a quantum mechanical oscillator I. Issues of principle. Rev. Mod. Phys. 52, 341–392 (1980).
Grangier, P., Levenson, A. L. & Poizat, J. P. Quantum non-demolition measurements in optics. Nature 396, 537–542 (1998).
Levenson, M. D., Shelby, R. M., Reid, M. & Walls, D. F. Quantum non-demolition detection of optical quadrature amplitudes. Phys. Rev. Lett. 57, 2473–2476 (1986).
La Porta, A., Slusher, R. E. & Yurke, B. Back-action evading measurements of an optical field using parametric down-conversion. Phys. Rev. Lett. 62, 28–31 (1989).
Friberg, S. R., Machida, S. & Yamamoto, Y. Quantum non-demolition measurement of the photon number of an optical soliton. Phys. Rev. Lett. 69, 3165–3168 (1992).
Roch, J. F., Roger, G., Grangier, P., Courty, J. M. & Reynaud, S. Quantum non-demolition measurements in optics: a review and some recent experimental results. Appl. Phys. B 55, 291–297 (1992).
Poizat, J. P. & Grangier P. Experimental realisation of a quantum optical tap. Phys. Rev. Lett. 70, 271–274 (1993).
Pereira, S. F., Ou, Z. Y. & Kimble, H. J. Back-action evading measurements for quantum non-demolition detection and quantum optical tapping. Phys. Rev. Lett. 72, 214–217 (1994).
Quantum non-demolition measurements. Appl. Phys. B 64(suppl.), 123–272 (1997).
Roch, J. F. et al. Quantum non-demolition measurements using cold atoms. Phys. Rev. Lett. 78, 634–637 (1997).
Bencheick, K., Levenson, J. A., Grangier, P. & Lopez, O. Quantum non-demolition demonstration via repeated back-action evading measurements. Phys. Rev. Lett. 75, 3422–3425 (1995).
Bruckmeier, R., Hansen, H. & Schiller, S. Repeated quantum non-demolition measurements of continuous optical waves. Phys. Rev. Lett. 79, 1463–1466 (1997).
Haroche, S. & Raimond, J. M. Cavity quantum electrodynamics. Sci. Am. 268, 54–62 (1993).
Barenco, A., Deutsch, D. & Ekert, A. Conditional quantum dynamics and logic gates. Phys. Rev. Lett. 74, 4083–4086 (1995).
Haroche, S. Atoms and photons in high Q cavities: new tests of quantum theory. Ann. NY Acad. Sci. 755, 73–86 (1995).
Brune, M. et al. Quantum Rabi oscillation: a direct test of field quantization in a cavity. Phys. Rev. Lett. 76, 1800–1803 (1996).
Rauch, H., Zeilinger, A., Badurek, G. & Wilfing, A. Verification of coherent spinor rotation of fermions. Phys. Lett. A 54, 425–427 (1975).
Werner, S. A., Colella, R., Overhauser, A. W. & Eagen, C. F. Observation of the phase shift of a neutron due to the precession in a magnetic field. Phys. Rev. Lett. 35, 1053–1055 (1975).
Ramsey, N. F. Molecular Beams (Oxford Univ. Press, New York, (1985).
Brune, M., Haroche, S., Lefèvre, V., Raimond, J. M. & Zagury, N. Quantum non-demolition measurement of small photon numbers by Rydberg atom phase-sensitive detection. Phys. Rev. Lett. 65, 976–979 (1990).
Brune, M., Haroche, S., Raimond, J. M., Davidovich, L. & Zagury, N. Manipulation of photons in a cavity by dispersive atom-field coupling: quantum non-demolition measurements and generation of Schrödinger cat states. Phys. Rev. A 45, 5193–5214 (1992).
Bragingsky, V. B. & Khalili, F. Ya. Quantum non-demolition measurements: the route from toys to tools. Rev. Mod. Phys. 68, 1–11 (1996).
Weidinger, M., Varcoe, B., Heerlein, R. & Walther, H. Trapping states in the micromaser. Phys. Rev. Lett. 82, 3795–3798 (1999).
Brune, M. et al. Observing the progressive decoherence of the meter in a quantum measurement. Phys. Rev. Lett. 77, 4887–4889 (1996).
Hagley, E. et al. Generation of Einstein-Podolsky-Rosen pairs of atoms. Phys. Rev. Lett. 79, 1–5 (1997).
Maître, X. et al. Quantum memory with a single photon in a cavity. Phys. Rev. Lett. 79, 769–772 (1997).
Hulet, R. G. & Kleppner, D. Rydberg atoms in “circular” states. Phys. Rev. Lett. 51, 1430–1433 (1983).
Nussenzveig, P. et al. Preparation of high principal quantum numbers “circular” states of rubidium. Phys. Rev. A 48, 3991–3994 (1993).
Laboratoire Kastler Brossel is a Unité Mixte de Recherches of Ecole Normale Supérieure, Université P. et M. Curie, and Centre National de la Recherche Scientifique. This work was supported by the Commission of the European Community.
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Nogues, G., Rauschenbeutel, A., Osnaghi, S. et al. Seeing a single photon without destroying it. Nature 400, 239–242 (1999). https://doi.org/10.1038/22275
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