Light-shift-induced photonic nonlinearities (original) (raw)
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Perspectives for quantum state engineering via high nonlinearity in a double-EIT regime
Journal of Modern Optics, 2003
We analyse the possibilities for quantum state engineering offered by a model for Kerr-type nonlinearity enhanced by electromagnetically induced transparency (EIT), which was recently proposed by Petrosyan and Kurizki [Phys. Rev. A 65, 33833 (2002)]. We go beyond the semiclassical treatment and derive a quantum version of the model with both a full Hamiltonian approach and an analysis in terms of dressed states. The preparation of an entangled coherent state via a crossphase modulation effect is demonstrated. We briefly show that the violation of locality for such an entangled coherent state is robust against low detection efficiency. Finally, we investigate the possibility of a bi-chromatic photon blockade realized via the interaction of a low density beam of atoms with a bi-modal electromagnetic cavity which is externally driven. We show the effectiveness of the blockade effect even when more than a single atom is inside the cavity. The possibility to control two different cavity modes allows some insights into the generation of an entangled state of cavity modes.
Deterministic quantum nonlinear optics with single atoms and virtual photons
Physical Review A, 2017
We show how analogues of a large number of well-known nonlinear-optics phenomena can be realized with one or more two-level atoms coupled to one or more resonator modes. Through higher-order processes, where virtual photons are created and annihilated, an effective deterministic coupling between two states of such a system can be created. In this way, analogues of three-wave mixing, four-wave mixing, higher-harmonic and-subharmonic generation (i.e., up-and downconversion), multiphoton absorption, parametric amplification, Raman and hyper-Raman scattering, the Kerr effect, and other nonlinear processes can be realized. In contrast to most conventional implementations of nonlinear optics, these analogues can reach unit efficiency, only use a minimal number of photons (they do not require any strong external drive), and do not require more than two atomic levels. The strength of the effective coupling in our proposed setups becomes weaker the more intermediate transition steps are needed. However, given the recent experimental progress in ultrastrong light-matter coupling and improvement of coherence times for engineered quantum systems, especially in the field of circuit quantum electrodynamics, we estimate that many of these nonlinear-optics analogues can be realized with currently available technology.
Atom-field entanglement in cavity QED: Nonlinearity and saturation
Physical Review A
We investigate the degree of entanglement between an atom and a driven cavity mode in the presence of dissipation. Previous work has shown that in the limit of weak driving fields, the steady state entanglement is proportional to the square of the driving intensity. This quadratic dependence is due to the generation of entanglement by the creation of pairs of photons/excitations. In this work we investigate the entanglement between an atom and a cavity in the presence of multiple photons. Nonlinearity of the atomic response is needed to generate entanglement, but as that nonlinearity saturates the entanglement vanishes. We posit that this is due to spontaneous emission, which puts the atom in the ground state and the atom-field state into a direct product state. An intermediate value of the driving field, near the field that saturates the atomic response, optimizes the atomfield entanglement. In a parameter regime for which multiphoton resonances occur, we find that entanglement recurs at those resonances. In this regime, we find that the entanglement decreases with increaing photon number. We also investigate, in the bimodal regime, the entanglement as a function of atom and/or cavity detuning. Here we find that there is evidence of a phase transition in the entanglement, which occurs at 2 /g ≥ 1.
Cavity Nonlinear Optics at Low Photon Numbers from Collective Atomic Motion
Physical Review Letters, 2007
We report on Kerr nonlinearity and dispersive optical bistability of a Fabry-Perot optical resonator due to the displacement of ultracold atoms trapped within. In the driven resonator, such collective motion is induced by optical forces acting upon up to 10 5 87 Rb atoms prepared in the lowest band of a one-dimensional intracavity optical lattice. The longevity of atomic motional coherence allows for strongly nonlinear optics at extremely low cavity photon numbers, as demonstrated by the observation of both branches of optical bistability at photon numbers below unity.
Nonlinear spectroscopy of photons bound to one atom
Nature Physics, 2008
Optical nonlinearities typically require macroscopic media, thereby making their implementation at the quantum level an outstanding challenge. Here we demonstrate a nonlinearity for one atom enclosed by two highly reflecting mirrors . We send laser light through the input mirror and record the light from the output mirror of the cavity. For weak laser intensity, we find the vacuum-Rabi resonances . But for higher intensities, we find an additional resonance . It originates from the fact that the cavity can accommodate only an integer number of photons and that this photon number determines the characteristic frequencies of the coupled atom-cavity system . We selectively excite such a frequency by depositing at once two photons into the system and find a transmission which increases with the laser intensity squared. The nonlinearity differs from classical saturation nonlinearities and is direct spectroscopic proof of the quantum nature of the atom-cavity system. It provides a photon-photon interaction by means of one atom, and constitutes a step towards a two-photon gateway or a single-photon transistor .
Journal of Modern Optics, 2022
We present detailed numerical simulations of semiclassical and quantum spectra of a cavity quantum electrodynamics system consisting of a single three-level atom in Λ-configuration with one of its transitions strongly interacting with a quantized cavity mode while the other is driven by a coherent classical field. After deriving the equations of motion for the expected values of the system operators from the master equation, we compute numerically the semiclassical and quantum spectra of the system under various levels of external driving field strengths. In the semiclassical approach we neglect the quantum correlations between cavity and atomic operators, while we make no such assumption in the fully quantum approach. We show that, under sufficiently weak driving field conditions, the semiclassical and fully quantum mechanical approaches result in identical spectra. However at higher driving field intensities, the two approaches yield starkly different results: The fully quantum mechanical approach results in multiphoton spectrum with well-defined structure while the semiclassical results in a bistable spectrum. Our results also reveal that the Raman transition mediated by the dark state of the system has a complex structure that depends on the manner in which the system is probed.
Physical Review Letters, 2011
We propose a waveguide-QED system where two single photons of distinct frequency or polarization interact strongly. The system consists of a single ladder-type three level atom coupled to a waveguide. When both optical transitions are coupled strongly to the waveguide's mode, we show that a control photon tuned to the upper transition induces a phase shift and tunneling of a probe photon tuned to the otherwise reflective lower transition. Furthermore, the system exhibits single photon scattering by a classical control beam. Waveguide-QED schemes could be an alternative to high quality cavities or dense atomic ensembles in quantum information processing.
Nonlinear spectroscopy of a three level atom strongly interacting with a quantized cavity mode
arXiv (Cornell University), 2019
We present detailed numerical simulations of semiclassical and quantum spectra of a cavity quantum electrodynamics system consisting of a single three-level atom in Λ-configuration with one of its transitions strongly interacting with a quantized cavity mode while the other is driven by a coherent classical field. After deriving the equations of motion for the expected values of the system operators from the master equation, we compute numerically the semiclassical and quantum spectra of the system under various levels of external driving field strengths. In the semiclassical approach we neglect the quantum correlations between cavity and atomic operators, while we make no such assumption in the fully quantum approach. We show that, under sufficiently weak driving field conditions, the semiclassical and fully quantum mechanical approaches result in identical spectra. However at higher driving field intensities, the two approaches yield starkly different results: The fully quantum mechanical approach results in multiphoton spectrum with well-defined structure while the semiclassical results in a bistable spectrum. Our results also reveal that the Raman transition mediated by the dark state of the system has a complex structure that depends on the manner in which the system is probed.
The European Physical Journal D, 2011
We propose a scheme for deterministic generation of entanglement embodied by two Λ-type atoms distributed in two coupled cavities. We study such a system in the dispersive atom-field interactions, where the dynamics of the system operates through the virtual population of both the atomic excited states and the photonic states in the cavities (plus the fiber). We verify the validity of the dynamics, and moreover, study the influences of the decoherence due to the spontaneous emission and photon leakage. We also apply the dynamics for realizing quantum state transfer and quantum phase gates.