Search results for "Coherent control"
showing 10 items of 34 documents
On-chip frequency combs and telecommunications signal processing meet quantum optics
2018
Entangled optical quantum states are essential towards solving questions in fundamental physics and are at the heart of applications in quantum information science. For advancing the research and development of quantum technologies, practical access to the generation and manipulation of photon states carrying significant quantum resources is required. Recently, integrated photonics has become a leading platform for the compact and cost-efficient generation and processing of optical quantum states. Despite significant advances, most on-chip nonclassical light sources are still limited to basic bi-photon systems formed by two-dimensional states (i.e., qubits). An interesting approach bearing …
Generation and Coherent Control of Pulsed Quantum Frequency Combs
2018
We present a method for the generation and coherent manipulation of pulsed quantum frequency combs. Until now, methods of preparing high-dimensional states on-chip in a practical way have remained elusive due to the increasing complexity of the quantum circuitry needed to prepare and process such states. Here, we outline how high-dimensional, frequency-bin entangled, two-photon states can be generated at a stable, high generation rate by using a nested-cavity, actively mode-locked excitation of a nonlinear micro-cavity. This technique is used to produce pulsed quantum frequency combs. Moreover, we present how the quantum states can be coherently manipulated using standard telecommunications…
Intensity Invariance of Strong-Field Two-Photon Absorption
2010
We demonstrate experimentally and theoretically the intensity-invariant scaling formula of coherent control of two-photon absorption as a function of pulse-shape parameters of ultrafast laser field in the strong-interaction regime.
Control of the coupling strength and linewidth of a cavity magnon-polariton
2020
The full coherent control of hybridized systems such as strongly coupled cavity photon-magnon states is a crucial step to enable future information processing technologies. Thus, it is particularly interesting to engineer deliberate control mechanisms such as the full control of the coupling strength as a measure for coherent information exchange. In this work, we employ cavity resonator spectroscopy to demonstrate the complete control of the coupling strength of hybridized cavity photon-magnon states. For this, we use two driving microwave inputs which can be tuned at will. Here, only the first input couples directly to the cavity resonator photons, whilst the second tone exclusively acts …
Ultrafast hybrid plasmonics
2008
Abstract We review our recent studies of electromagnetic coupling and associated temporal dynamics of molecular excitations with plasmonic resonances supported by either localized or extended planar geometries. We focus on coherent interactions between plasmon resonances and molecular excitations, which are experimentally challenging due to the very short (∼10–100 fs) coherence times of plasmons. Recent experimental results and theoretical analysis for observing and controlling coherences between molecular excitations and plasmonic polarizations are shown. Advances will explore new directions in ultrafast coherent control of molecular excited states and energy dissipation processes, as well…
Coherent control of stimulated emission inside one-dimensional photonic crystals
2004
In this paper, the quasinormal mode (QNM) theory is applied to discuss the quantum problem of an atom embedded inside a one-dimensional (1D) photonic band gap (PBG) cavity pumped by two counterpropagating laser beams. The e.m. field is quantized in terms of the QNMs in the 1D PBG and the atom modeled as a two-level system is assumed to be weakly coupled to just one of the QNMs. The main result of the paper is that the decay time depends on the position of the dipole inside the cavity, and can be controlled by the phase difference of the two laser beams.
On-chip Generation, Coherent Control and Processing of Complex Entangled Photon States
2019
We demonstrate the on-chip generation of time-bin entangled two- and multi-photon qubit states, as well as high-dimensional frequency-entangled photon pairs. Combining time and frequency entanglement, we generate high-dimensional optical cluster states and implement proof-of-concept high-dimensional one-way quantum computing. This, by using standard, fiber-based telecommunication components.
Coherent control via weak measurements in P31 single-atom electron and nuclear spin qubits
2018
The understanding of weak measurements and interaction-free measurements has greatly expanded the conceptual and experimental toolbox to explore the quantum world. Here we demonstrate single-shot variable-strength weak measurements of the electron and nuclear spin states of a P31 single-atom donor in silicon. We first show how the partial collapse of the nuclear spin due to measurement can be used to coherently rotate the spin to a desired pure state. We explicitly demonstrate that phase coherence is preserved with high fidelity throughout multiple sequential single-shot weak measurements and that the partial state collapse can be reversed. Second, we use the relation between measurement st…
Stratégies de contrôle pour la manipulation spatiale de molécules
2011
Talk given by E. Hertz; National audience
Coherent Control of the Rotational Degree of Freedom of a Two-Ion Coulomb Crystal.
2019
We demonstrate the preparation and coherent control of the angular momentum state of a two-ion crystal. The ions are prepared with an average angular momentum of 7850ℏ freely rotating at 100 kHz in a circularly symmetric potential, allowing us to address rotational sidebands. By coherently exciting these motional sidebands, we create superpositions of states separated by up to four angular momentum quanta. Ramsey experiments show the expected dephasing of the superposition which is dependent on the number of quanta separating the states. These results demonstrate coherent control of a collective motional state described as a quantum rotor in trapped ions. Moreover, our Letter offers an expa…