共查询到20条相似文献,搜索用时 31 毫秒
1.
Room temperature stable single-photon source 总被引:2,自引:0,他引:2
A. Beveratos S. Kühn R. Brouri T. Gacoin J.-P. Poizat P. Grangier 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):191-196
We report on the realization of a stable solid state room temperature source for single photons. It is based on the fluorescence
of a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. Antibunching has been observed in the fluorescence
light under both continuous and pulsed excitation. Our source delivers 2×104 s-1 single-photon pulses at an excitation repetition rate of 10 MHz. The number of two-photon pulses is reduced by a factor of
five compared to strongly attenuated coherent sources.
Received 1st August 2001 and Received in final form 2 October 2001 相似文献
2.
T. Aichele A.I. Lvovsky S. Schiller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):237-245
A detailed theoretical analysis of the spatiotemporal mode of a single photon prepared via conditional measurements on a photon pair generated in the process of parametric down-conversion is presented. The maximum
efficiency of coupling the photon into a transform-limited classical optical mode is calculated and ways for its optimization
are determined. An experimentally feasible technique of generating the optimally matching classical mode is proposed. The
theory is applied to a recent experiment on pulsed homodyne tomography of the single-photon Fock state [A.I. Lvovsky et al., Phys. Rev. Lett. 87, 050402 (2001)].
Received 16 July 2001 相似文献
3.
P.J. Edwards G.H. Pollard W.N. Cheung 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):147-153
Quantum key exchanges using weak coherent (Poissonian) single-photon sources are open to attack by a variety of eavesdropping
techniques. Quantum-correlated photon sources provide a means of flagging potentially insecure multiple-photon emissions and
thus extending the secure quantum key channel capacity and the secure key distribution range. We present indicative photon-counting
statistics for a fully correlated Poissonian multibeam photon source in which the transmitted beam is conditioned by photon
number measurements on the remaining beams with non-ideal multiphoton counters. We show that significant rejection of insecure
photon pulses from a twin-beam source cannot be obtained with a detector having a realistic quantum efficiency. However quantum-correlated
(quadruplet or octuplet) multiplet photon sources conditioned by high efficiency multiphoton counters could provide large
improvements in the secure channel capacity and the secure distribution range of high loss systems such as those using the
low earth orbit satellite links proposed for global quantum key distribution.
Received 14 July and Received in final form 20 November 2001 相似文献
4.
F. Grosshans P. Grangier 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):119-125
Homodyne detection can be used to perform measurements on various quantum states of the light, such as conditional single
photon states produced by parametric fluorescence processes. In the pulsed regime, the time and frequency overlap between
the single photon wave packet and the local oscillator field plays a crucial role. We show in this paper that this overlap
can be characterized by an effective quantum efficiency, which is explicitly calculated in various situations of experimental
interest.
Received 27 July 2000 and Received in final form 29 November 2000 相似文献
5.
Preparation of Fock states and quantum entanglement via stimulated Raman adiabatic passage using a four-level atom 总被引:3,自引:0,他引:3
S.-Q. Gong R. Unanyan K. Bergmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(2):257-262
We study the behaviour of an atom-cavity system exposed to a stimulated Raman adiabatic passage (STIRAP) process in a four-level
system, with a coupling scheme which generate two degenerate dark states. We find that the non-adiabatic interaction of the
two dark states guarantees that the cavity Fock states can always be generated by both intuitively and counterintuitively
ordered pulses. Furthermore, we propose a method to entangle two atoms. Depending on the ordering of the pulses two orthogonal
entangled states can be prepared. Since these entangled states do not have component of the excited states included, the technique
is robust against the detrimental consequences of spontaneous emission.
Received 20 March 2001 相似文献
6.
S.M. Barnett C. Fabre A. Maıtre 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):513-519
We compare two high sensitivity techniques which are used to measure very small displacements of physical objects by optical
techniques: the interferometric devices, measuring longitudinal phase shifts, and the devices used to monitor transverse displacement
of light beams. We detail the differences and the similarities for the quantum limits on the resolution of both systems. In
both cases squeezed light can be used to resolve beyond the standard quantum limit and number correlated states allow us to
reach the “Heisenberg” limit.
Received 12 September 2002 Published online 21 January 2003 相似文献
7.
E. Santos 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):423-431
Several examples of photon entanglement are studied in the Q representation of quantum optics. In particular, the entangled states produced in parametric downconversion are studied in
detail, and we determine the conditions for the violation of Bell's inequality. Our approach shows that photon entanglement
is related to the existence of correlations between the quantum fluctuations of the electromagnetic field associated to different
modes.
Received 10 August 2002 / Received in final form 7 November 2002 Published online 4 February 2003 相似文献
8.
P. Horak H. Ritsch 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):279-287
We propose a method to create macroscopic superpositions, so-called Schr?dinger cat states, of different motional states of
an ideal Bose-Einstein condensate. The scheme is based on the scattering of a freely expanding condensate by the light field
of a high-finesse optical cavity in a quantum superposition state of different photon numbers. The atom-photon interaction
creates an entangled state of the motional state of the condensate and the photon number, which can be converted into a pure
atomic Schr?dinger cat state by operations only acting on the cavity field. We discuss in detail the fully quantised theory
and propose an experimental procedure to implement the scheme using short coherent light pulses.
Received 26 June 2000 and Received in final form 2nd October 2000 相似文献
9.
J. Bylander I. Robert-Philip I. Abram 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):295-301
Two independent photons, produced through the spontaneous emission of two separate emitters subject to uncorrelated dephasing
processes, can display two-photon interference (i.e. coalescence into a two-photon state) when they are incident simultaneously on a beamsplitter, in a manner analogous to that
of twin photons produced through degenerate parametric fluorescence. The presence of dephasing processes, however, reduces
the interference contrast (i.e. the probability of coalescence), by the ratio of the coherence time to the lifetime of the emitter.
Received 9 September 2002 Published online 17 December 2002
RID="a"
ID="a"e-mail: izo.abram@lpn.cnrs.fr 相似文献
10.
E. Brambilla A. Gatti L.A. Lugiato M.I. Kolobov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(1):127-135
We analyze theoretically spatial structures appearing in the far diffraction zone of the electromagnetic field emitted in
the cavityless parametric down-conversion. We investigate in detail the spatial correlation functions of intensity and demonstrate
the existence of strong quantum correlations between the regions of the far field symmetrical with respect to the optical
axis. Our simplified model allows us to obtain analytical results for some limiting cases. We demonstrate that in the limit
of small diffraction and ideal quantum efficiency of photodetection the noise reduction in the photocurrent difference between
symmetrical regions in the far diffraction field becomes complete at zero frequency of photocurrent fluctuations.
Received 5 February 2001 and Received in final form 11 April 2001 相似文献
11.
L. Vernac M. Pinard V. Josse E. Giacobino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):129-135
Using a quantum theory for an ensemble of two- or three-level atoms driven by electromagnetic fields in an optical cavity,
we show that the various spins associated with the atomic ensemble can be squeezed. Two kinds of squeezing are obtained: on
the one hand self-spin squeezing when the input fields are coherent ones and the atomic ensemble exhibits a large non-linearity;
on the other hand squeezing transfer when one of the incoming fields is squeezed.
Received 14 August 2001 and Received in final form 7 November 2001 相似文献
12.
N. Korolkova Ch. Silberhorn O. Glöckl S. Lorenz Ch. Marquardt G. Leuchs 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):229-235
We present schemes for the generation and evaluation of continuous variable entanglement of bright optical beams and give
a brief overview of a variety of optical techniques and quantum communication applications on this basis. A new entanglement-based
quantum interferometry scheme with bright beams is suggested. The performance of the presented schemes is independent of the
relative interference phase which is advantageous for quantum communication applications.
Received 1st August 2001 相似文献
13.
A. Messina 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):379-383
A new conditional scheme for generating Bell states of two spatially separated high-Q cavities is reported. Our method is based on the passage of one atom only through the two cavities. A distinctive feature
of our treatment is that it incorporates from the very beginning the unavoidable presence of fluctuations in the atom-cavity
interaction times. The possibility of successfully implementing our proposal against cavity losses and atomic spontaneous
decay is carefully discussed.
Received 31 July 2001 and Received in final form 9 October 2001 相似文献
14.
A. Bramati J.-P. Hermier V. Jost E. Giacobino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(3):421-427
The combined effects of the pump noise suppression and injection locking technique on the intensity noise of a diode pumped
Nd:YVO4 microchip laser are theoretically and experimentally investigated. Complete cancellation of the relaxation oscillation peak
is experimentally achieved. Very good agreement between experimental results and theoretical predictions of a fully quantum
model describing lasers with injected signal is found.
Received 10 December 2001 and Received in final form 6 March 2002 相似文献
15.
J.-M. Merolla L. Duraffourg J.-P. Goedgebuer A. Soujaeff F. Patois W.T. Rhodes 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):141-146
We report a new quantum cryptographic system involving single sideband detection and allowing an implementation of the BB84
protocol. The transmitted bits are reliably coded by the phase of a high frequency modulating signal. The principle of operation
is described in terms of both classical and quantum optics. The method has been demonstrated experimentally at 1 550 nm using
compact and conventional device technology. Single photon interference has been obtained with a fringe visibility greater
than 98%, indicating that the system can be used in view of quantum key distribution potentially beyond 50-km-long standard
single-mode fiber.
Received 13 July 2001 and Received in final form 30 November 2001 相似文献
16.
W.L. Barnes G. Björk J.M. Gérard P. Jonsson J.A.E. Wasey P.T. Worthing V. Zwiller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):197-210
We examine the problem of efficiently collecting the photons produced by solid-state single photon sources. The extent of
the problem is first established with the aid of simple physical concepts. Several approaches to improving the collection
efficiency are then examined and are broadly categorized into two types. First are those based on cavity quantum dynamics,
in which the pathways by which the source may emit a photon are restricted, thus channeling emission into one desired mode.
Second are those where we try to reshape the free space modes into a target mode in an optimal way, by means of refraction,
without fundamentally altering the way in which the source emits. Respectively, we examine a variety of microcavities and
solid immersion lenses. Whilst we find that the micropillar microcavities offer the highest collection efficiency (∼70%),
choosing this approach may not always be appropriate due to other constraints. Details of the different approaches, their
merits and drawbacks are discussed in detail.
Received 19 July 2001 and Received in final form 5 October 2001 相似文献
17.
U. Yurtsever D. Strekalov J.P. Dowling 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):365-371
A quantum gravity-gradiometer consists of two spatially separated ensembles of atoms interrogated by pulses of a common laser
beam. The laser pulses cause the probability amplitudes of atomic ground-state hyperfine levels to interfere, producing two,
motion-sensitive, phase shifts, which allow the measurement of the average acceleration of each ensemble, and, via simple
differencing, of the acceleration gradient. Here we propose entangling the quantum states of atoms from the two ensembles
prior to the pulse sequence, and show that entanglement encodes their relative acceleration in a single interference phase
which can be measured directly, with no need for differencing.
Received 6 June 2002 / Received in final form 25 October 2002 Published online 28 January 2003 相似文献
18.
Y. Shih 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):485-493
One of the most surprising consequences of quantum mechanics is the entanglement of two or more distant particles. Even though
we still have questions in regard to fundamental issues of the entangled quantum systems, quantum entanglement has started
to play important roles in practical applications. Quantum imaging is one of the hot topics. Quantum imaging has many interesting
features which are useful for different applications. For example, quantum imaging can be nonlocal, which is useful for secure
two-dimensional information transfer. Quantum imaging can reach a much higher spatial resolution comparing with classical
imaging, even beyond the diffraction limit, which is useful for lithography and other microsystem fabrication technology.
It is not a violation of the uncertainty principle, however, a quantum mechanical multi-particle phenomenon.
Received 30 August 2002 / Received in final form 11 November 2002 Published online 4 February 2003 相似文献
19.
M. Schnürer S. Ter-Avetisyan H. Stiel U. Vogt W. Radloff M. Kalashnikov W. Sandner P.V. Nickles 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(3):331-335
Using 50 fs ( ∼ 2×1018 W/cm2) and 2 ps ( ∼ 5×1016 W/cm2) pulses from a Ti:Sa multi-TW laser at 800 nm wavelength large Xe-clusters ( 105...106 atoms per cluster) have been excited. Absolute yield measurements of EUV-emission in a wavelength range between 10 nm and
15 nm in combination with cluster target variation were carried out. The ps-laser pulse has resulted in about 30% enhanced
and spatially more uniform EUV-emission compared to fs-laser excitation. Circularly polarized laser light instead of linear
polarization results in enhanced emission which is probably caused by electrons gaining higher energies by the polarization
dependent optical field ionization process. An absolute emission efficiency at 13.4 nm of up to 0.8% in 2π sr and 2.2% bandwidth
has been obtained.
Received 11 January 2001 and Received in final form 27 March 2001 相似文献
20.
Shor and Preskill's and Mayers's security proof for the BB84 quantum key distribution protocol 总被引:1,自引:0,他引:1
D. Mayers 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):161-170
We review two security proofs for the BB84 quantum key distribution protocol: Mayers's security proof and the more recent
proof of Shor and Preskill. We focus on the basic principles and the intuition in Mayers's proof instead of technical details.
We present a variation on Shor's and Preskill's proof which is convenient for purpose of comparison. We explain the connection
between these two proofs.
Received 14 July 2001 相似文献