Deterministic source of a train of indistinguishable single-photon pulses with a single-atom-cavity system

Abstract

We present a mechanism to produce indistinguishable single-photon pulses on demand from an optical cavity. The sequences of two laser pulses generate, at the two Raman transitions of a four-level atom, the same cavity-mode photons without repumping of the atom between photon generations. Photons are emitted from the cavity with near-unit efficiency in well-defined temporal modes of identical shapes controlled by the laser fields. The second order correlation function reveals the single-photon nature of the proposed source. A realistic setup for the experimental implementation is presented. [5], is to have single photon pulses with well-defined identical shapes, frequency and polarization, as these schemes based on photoninterference effects are very sensitive to the parameters of SP pulses and their repetition rate. A good source has to ensure a pure SP state without mixture from both the multi-photon and zero-photon states, as well as to prevent the entanglement between the photons which degrades the purity of the SP state. Since the individual photons are usually emitted during the spontaneous decay of atomic systems, the SP sources must be immune to the environmental effects that induce the dephasing of atomic transitions. Most of the schemes proposed earlier to produce single photons on demand from solid state single emitters [6], organic molecules [7,8], and quantum dots [9,10] are confronted with this difficulty. Besides, they do not offer a high efficiency because of the isotropic nature of fluorescence that prevents to collect the photons, not to mention the spectral dephasing and inhomogeneity of solid-state emitters. Deterministic sources of single photons are realized also in cold atomic ensembles with feedback circuit [11,12]. But these schemes are not suitable to generate SP train with an arbitrary repetition rate because of strong temporary bounds caused by the feedback and write-read processes.At present, all the requirements mentioned above can be achieved together with a Λ-type atom trapped in highfinesse optical cavities [13][14][15][16], where the single photons are generated via vacuum-stimulated Raman scattering of a classical laser field into a cavity mode. These systems * Electronic address: yumal@ipr.sci.am not only provide a strong interaction between a photon and an atom, but also support very high collection efficiency due to the fact that the photons leave the cavity through one mirror with a transmissivity incomparably larger than that of the opposite one. By carefully adjusting the parameters of the laser pulse one can also easily control the waveform of output single photons. However, the main disadvantage of these schemes is the necessity to use a repumping field to transfer the population of the atom to its initial state after the generation of a cavity photon and only then to generate the next one. In this Letter we propose a scheme featuring a double Raman atomic configuration, which is able to deterministically generate a stream of identical SP pulses without using the repump...

Deterministic quantum state transfer between remote atoms with photon-number superposition states

“…The present mechanism for producing PNSS is based on our earlier proposed method of deterministic generation of a stream of multiphoton pulses in a single-atomsingle-mode cavity QED system [31,32]. A multi-level atom or ion is trapped in a one-mode high-finesse optical cavity and interacts with a σ + -polarized laser field Ω 1 (Fig.1a) on the multi-level chain, for instance, on the transition 5S 1/2 (F = 1) → 5P 3/2 (F ′ = 2) of the 87 Rb atom, where the state 5P 3/2 (F ′ = 2) is well isolated from other hyperfine levels.…”

EIT-based quantum memory for single photons from cavity-QED

“…The latter timescale is normally the longest, lasting several microseconds, thus limiting the repetition rate to hundreds of kHz [42]. A technique to produce polarizationcontrolled photons from the cavity by shifting the laser frequency between Zeeman sub-states removes the need for repumping and can increase the repetition rate to MHz [51,52]. Fig.…”

High-efficiency single-photon Fock state production by transitionless quantum driving

“…In the far-off-resonant case, the upper atomic state |e m can be effectively eliminated [17], i.e.,Ċ 4 = 0. As a consequence, an effective Raman atom-photon coupling Ω 1 = Ω m g m /∆ m is delivered [18], and then the above double Λ-level atom-cavity system is reduced to an effective three-level Λ one (see Fig.…”

“…Here, with the full quantized atom-cavity interaction we discuss how to apply the TQD technique to achieve the high efficiency single-photon FSP with the usual double Λ-level atom interacting with a single-mode high-Q cavity. Although the similar configuration had been used to implement the production of single photon by using the STIRAP technique (see, e.g., [16,17,18]), the present proposal possesses a manifest advantage: the population transfer for the FSP could be implemented fast (as it is beyond the adiabatic limit) and deterministically (as it does not yield any unwanted leakage from the driven states). Therefore, the desirable FSP can be achieved with a significantly high efficiency.…”

“…It is seen that, the energy invariant subspace related to the HamiltonianĤ R (t) is formed by the following dressed states: |g 1 , 0 , |e, 0 , |e m , 0 and |g 2 , 1 (here we assume that the cavity mode is initially prepared in the vacuum state |0 ). Thus, the desirable single-photon FSP requires the system should be manipulated deterministically from the ground state |g 1 , 0 to the target state |g 2 , 1 [16,17,18]. Although this progress had been achieved by the STIRAP technique with a Λ-level atom-cavity system, the efficiency of the desirable FSP is significantly limited due to the undesired non-adiabatic transitions.…”