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SUMMARY:Single-Photon shaping and phase control - Axel Kuhn (Oxford Univer
 sity)
DTSTART:20111107T153000Z
DTEND:20111107T170000Z
UID:TALK33847@talks.cam.ac.uk
CONTACT:6270
DESCRIPTION:Single-Photon Shaping and Phase Control\n\nAxel Kuhn\nUniversi
 ty of Oxford\, Clarendon Laboratory\, Parks Road\, Oxford OX1 3PU\, United
  Kingdom\n\n\nWe investigate light-matter interfaces for quantum networkin
 g based on vacuum-stimulated rapid adiabatic passage in coupled atom-cavit
 y systems [1-4]. Our recent results show that 87Rb atoms crossing a cavity
  in free flight provide a unique way of deterministically generating a str
 eam of single photons of small bandwidth [5]. The atoms are injected into 
 the cavity with an atomic fountain\, which gives rise to atom-cavity inter
 action times of up to 0.5 ms. With a suitably tailored driving laser pulse
 \, the temporal shape and phase evolution of the photons can be controlled
  arbitrarily [2]. This is monitored with a two-photon interference experim
 ent of the Hong-Ou-Mandel type. \nThe high repetition rate and efficiency 
 of our deterministic photon source pave the way to N-photon LOQC experimen
 ts\, with the phase and shape control allowing for the encoding of any pos
 sible qubit superposition state in photonic time bins.\nBased on the succe
 ssful photon generation\, we also discuss inversion of the process to abso
 rbs a single impinging photon of arbitrary shape with a probability close 
 to unity. To do so\, we analytically derive the shape of the driving pulse
  required to maintain impedance matching of the cavity to the incoming pho
 tonic wavepacket throughout its whole duration [4]. \nWe furthermore repor
 t on the control of trapped atoms with optical tweezers [6]. This new tech
 nique allows handling many atoms independently\, and therefore paves the w
 ay to QIP with scalable atomic arrays.\n\n[1] 	A. Kuhn and D. Ljunggren\, 
 “Cavity-based single-photon sources\,” Contemporary Physics 51\, 289 (
 2010)\n[2] 	G.S. Vasilev\, D. Ljunggren\, and A. Kuhn\, “Single-photons 
 made-to-measure\,” New Journal of Physics 12\, 063024 (2010)\n[3] 	M. Hi
 msworth\, P.B.R. Nisbet\, J. Dilley\, G. Langfahl-Klabes\, and A. Kuhn\, 
 “EIT-based quantum memory for single photons from cavity-QED\,” Appl. 
 Phys. B 103\, 579-589 (2011)\n[4]	J. Dilley\, P.B.R. Nisbet\, B.W. Shore\,
  and A. Kuhn\, “Cavity-based single-atom quantum memory\,” submitted\,
  arXiv:1105:1699 [quant-ph]\n[5]	P. Nisbet\, J. Dilley\, and A. Kuhn\, “
 Highly efficient source for indistinguishable photons of controlled shape\
 ,” New Journal of Physics\, accepted\, arXiv:1106.6292v1 [quant-ph].\n[6
 ]	L. Brandt\, C. Muldoon\, T. Thiele\, J. Dong\, E. Brainis\, and A. Kuhn\
 , “Spatial light modulators for the manipulation of individual atoms\,
 ” Appl. Phys. B 102\, 443-450 (2011)\n
LOCATION:Rutherford building\, Seminar Room B
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