113 citations · 395 across the 20 of their papers we have counts for
21 papers
An asymmetric atom-photon architecture for device-independent quantum key distribution over 25 km
Jonas Meiers, Christian Haen, Max Bergerhoff +4
Device-independent quantum key distribution (DIQKD) can guarantee security without trusting the internal workings of the measurement devices, but extending it to fiber networks dem…
Indistinguishability of single Raman photons from single atoms
Pascal Baumgart, Max Bergerhoff, Jürgen Eschner
We theoretically investigate the indistinguishability of single photons generated from single trapped Ca ions in a Raman scattering process driven by few-nanosecond exci…
Telecom-compatible polarization-to-time-bin conversion of atom-photon entanglement for heterogeneous quantum networks
Christian Haen, Julian Groß-Funk, Max Bergerhoff +5
A key enabling feature of future quantum networks is interoperability between platforms that operate at different wavelengths and with different qubit encodings. We demonstrate an…
Quantum repeater segment with free-space coupled co-trapped ions using telecom photon interference
Max Bergerhoff, Pascal Baumgart, Christian Haen +5
A quantum repeater segment is a basic building block of a quantum repeater, generating buffered entanglement of quantum memories to connect quantum repeater cells. It also enables…
Indistinguishability of photonic qubits emitted from trapped Ca ions via pulsed excitation
Pascal Baumgart, Max Bergerhoff, Jonas Meiers +2
We investigate the indistinguishability of Raman photons generated from two trapped Ca ions using few-nanosecond excitation pulses. We elucidate how spontaneous scatteri…
Demonstration of quantum network protocols over a 14-km urban fiber link
Stephan Kucera, Christian Haen, Elena Arenskötter +9
We report on the implementation of quantum entanglement distribution and quantum state teleportation over a 14.4-km urban dark-fiber link, which is partially underground, partially…
Quantum repeater node with free-space coupled trapped ions
Max Bergerhoff, Omar Elshehy, Stephan Kucera +2
The quantum repeater cell is a basic building block for a quantum network, as it allows to overcome the distance limitations due to unavoidable fiber loss in direct transmission. W…
Calibration-Independent Certification of a Quantum Frequency Converter
Matthias Bock, Pavel Sekatski, Jean-Daniel Bancal +5
We report on a method to certify a unitary operation with the help of source and measurement apparatuses whose calibration throughout the certification process needs not be trusted…
Full Bell-basis measurement of an atom-photon 2-qubit state and its application for quantum networks
Elena Arenskötter, Stephan Kucera, Omar Elshehy +4
The efficiency of a Bell-state measurement on photon pairs is bound to 50\,\% due to the number of Bell states that can be distinguished using linear optics. Here we present the im…
Spectral properties of single photons from quantum emitters
Philipp Müller, Tristan Tentrup, Marc Bienert +2
Quantum networks require flying qubits that transfer information between the nodes. This may be implemented by means of single atoms (the nodes) that emit and absorb single photons…
Doubly-heralded single-photon absorption by a single atom
José Brito, Stephan Kucera, Pascal Eich +2
We report on a single-photon-to-single-atom interface, where a single photon generated by Spontaneous Parametric Down Conversion (SPDC) is absorbed by a single trapped ion. The pho…
Telecom-heralded single photon absorption by a single atom
Andreas Lenhard, Matthias Bock, Stephan Kucera +5
We present, characterize, and apply a photonic quantum interface between the near infrared and telecom spectral regions. A singly resonant optical parametric oscillator (OPO) opera…
Quantum interference in the absorption and emission of single photons by a single ion
Michael Schug, Christoph Kurz, Pascal Eich +3
We investigate quantum beats in the arrival-time distribution of single photons from a single trapped Ca ion, revealing their fundamentally different physical origins in…
A high-rate source for single photons in a pure quantum state
Christoph Kurz, Jan Huwer, Michael Schug +2
We report on the efficient generation of single photons, making use of spontaneous Raman scattering in a single trapped ion. The photons are collected through in-vacuum high-NA obj…
Heralded single photon absorption by a single atom
Nicolas Piro, Felix Rohde, Carsten Schuck +7
The emission and absorption of single photons by single atomic particles is a fundamental limit of matter-light interaction, manifesting its quantum mechanical nature. At the same…
Polarization-correlated photon pairs from a single ion
F. Rohde, J. Huwer, N. Piro +4
In the fluorescence light of a single atom, the probability for emission of a photon with certain polarization depends on the polarization of the photon emitted immediately before…
Two-color photoionization of calcium using SHG and LED light
C. Schuck, F. Rohde, M. Almendros +2
We present a photoionization method to load single 40Ca ions in a linear Paul trap from an atomic beam. Neutral Ca I atoms are resonantly excited from the ground state to the inter…
A diode laser stabilization scheme for 40Ca+ single ion spectroscopy
F. Rohde, M. Almendros, C. Schuck +3
We present a scheme for stabilizing multiple lasers at wavelengths between 795 and 866 nm to the same atomic reference line. A reference laser at 852 nm is stabilized to the Cs D2…
Resonant interaction of a single atom with single photons from a down-conversion source
C. Schuck, F. Rohde, N. Piro +7
We observe the interaction of a single trapped calcium ion with single photons produced by a narrow-band, resonant down-conversion source [A. Haase et al., Opt. Lett. 34, 55 (2009)…
Bandwidth-tunable single photon source in an ion trap quantum network
M. Almendros, J. Huwer, N. Piro +5
We report a tunable single-photon source based on a single trapped ion. Employing spontaneous Raman scattering and in-vacuum optics with large numerical aperture, single photons ar…
Polarization-based Light-Atom Quantum Interface with an All-optical Trap
Marcin Kubasik, Marco Koschorreck, Mario Napolitano +5
We describe the implementation of a system for studying light-matter interactions using an ensemble of cold rubidium 87 atoms, trapped in a single-beam optical dipole trap.…