A5056996132- Quantum Information and Cryptography
- Quantum optics and atomic interactions
- Quantum Mechanics and Applications
- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Semiconductor Lasers and Optical Devices
- Quantum Computing Algorithms and Architecture
- Cold Atom Physics and Bose-Einstein Condensates
- Optical Network Technologies
- Advanced Photonic Communication Systems
- Quantum and electron transport phenomena
- Neural Networks and Reservoir Computing
- Mechanical and Optical Resonators
- Thermal Radiation and Cooling Technologies
- Advanced Fiber Laser Technologies
- Scientific Measurement and Uncertainty Evaluation
- Surface and Thin Film Phenomena
- Strong Light-Matter Interactions
- Advanced Chemical Physics Studies
- Quantum-Dot Cellular Automata
- Spectroscopy and Quantum Chemical Studies
- Atomic and Subatomic Physics Research
- nanoparticles nucleation surface interactions
- Advanced Frequency and Time Standards
Toshiba (United Kingdom)
2015-2023
Saarland University
2013-2014
Institute of Photonic Sciences
2009-2013
University of Freiburg
2009
It would be terrific to use semiconductor quantum dots produce entangled photons in a communication network, but entanglement is complicated by the exciton spin splitting of typical dots. The authors present growth strategy that improves in-plane aspect ratio $I\phantom{\rule{0}{0ex}}I\phantom{\rule{0}{0ex}}I-V$ 72%, greatly reducing fine-structure eigenstates root problem. Their approach can implemented with either molecular-beam or vapor-phase epitaxy, yield emit at telecommunication...
The development of efficient sources single photons and entangled photon pairs emitting in the low-loss wavelength region around 1550 nm is crucial for long-distance quantum communication. Moreover, direct fiber coupling electrical carrier injection are highly desirable deployment compact user-friendly systems integrated with existing infrastructure. Here we present a detailed design study circular Bragg gratings fabricated InP slabs operating telecom C-band. These devices enable...
Although many properties of polyatomic metal clusters have been rationalized by an electron shell model resembling that used for free atoms, it remained unclear how reliable this analogy is with respect to the angular momentum eigenstate character electronic wave functions. We studied size-selected negatively charged sodium atoms (Na n – ) approximately spherical shape ( = 19, 40, 55, 58, 147) angle-resolved photoelectron spectroscopy over a broad range photon energies (1.5 5 volts). Highly...
Semiconductor quantum dots embedded in hybrid circular Bragg gratings are a promising platform for the efficient generation of nonclassical light. The scalable fabrication multiple devices with similar performance is highly desirable their practical use as sources single and entangled photons, while ability to operate at telecom wavelength essential integration existing fiber infrastructure. In this work, we combine properties broadband membrane-transfer process performed on 3 in. wafer...
The development of quantum relays for long haul and attack-proof communication networks operating with weak coherent laser pulses requires entangled photon sources at telecommunication wavelengths intrinsic single-photon emission most practical implementations. Using a semiconductor dot emitting pairs in the telecom O-band, we demonstrate first time relay fulfilling both these conditions. system achieves maximum fidelity 94.5 % implementation standard 4-state protocol input states generated...
Abstract Entangled light sources are considered as core technology for multiple quantum network architectures. Of particular interest that based on a single system these offer intrinsic security due to the sub-Poissonian nature of photon emission process. This is important applications in communication where multi-pair generally compromises performance. A large variety has been developed, but generated photons remained far from being utilized established standard fiber networks, mainly lack...
We report a tunable single-photon source based on single trapped ion. Employing spontaneous Raman scattering and in-vacuum optics with large numerical aperture, photons are efficiently created controlled temporal shape coherence time. These can be varied between 70 ns $1.6\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$, as characterized by operating two sources simultaneously in remote ion traps which reveals mutual individual through two-photon interference.
We establish a heralded interaction between two remotely trapped single $^{40}\mathrm{Ca}^{+}$ ions through the exchange of photons. In sender ion, we release photons with controlled temporal shape on ${P}_{3/2}$ to ${D}_{5/2}$ transition and transmit them distant receiver ion. Individual absorption events in ion are detected by quantum jumps. For continuously generated photons, reduces significantly lifetime long-lived state. triggered single-photon transmission, observe coincidence...
We report on the efficient generation of single photons, making use spontaneous Raman scattering in a trapped ion. The photons are collected through in-vacuum high-numerical-aperture objectives. Photon frequency, polarization and temporal shape controlled appropriate laser parameters, allowing for pure quantum state. These suitable heralds single-photon absorption single-ion memory.
We observe the interaction of a single trapped calcium ion with photons produced by narrow-band, resonant down-conversion source [A. Haase et al., Opt. Lett. 34, 55 (2009)], employing quantum jump scheme. Using temperature dependence spectrum and tunability narrow source, absorption is quantitatively characterized.
We present a scheme for stabilizing multiple lasers at wavelengths between 795 and 866 nm to the same atomic reference line. A laser 852 is stabilized Cs D2 line using Doppler-free frequency modulation technique. Through transfer cavities, four are relevant transitions in 40Ca+. The rms linewidth of transfer-locked measured be 123 kHz with respect an independent reference, Rb D1 This stability confirmed by comparison excitation spectrum single 40Ca+ ion eight-level Bloch equation model....
We use a single trapped 40Ca+ ion as resonant, polarization-sensitive absorber to detect and characterize the entanglement of tunable narrowband photon pairs from spontaneous parametric down-conversion source. Single-photon absorption is marked by quantum jump in heralded coincident detection partner photon. For three polarization basis settings herald, we find maximum coincidences always for orthogonal polarizations. The further evidenced tomographic reconstruction biphoton state with an...
High-contrast quantum beats in the single-photon scattering probability of a single atomic ion are experimentally observed and controlled, highlighting two distinct physical mechanisms, interference absorption emission.
We report on resonance fluorescence from a single quantum dot emitting at telecom wavelengths. perform high-resolution spectroscopy and observe the Mollow triplet in Rabi regime—a hallmark of fluorescence. The measured resonance-fluorescence spectra allow us to rule out pure dephasing as significant decoherence mechanism these dots. Combined with numerical simulations, experimental results provide robust characterisation charge noise environment dot. Resonant control opens up new...
Entangled light emitting diodes based on semiconductor quantum dots are promising devices for security sensitive network applications, thanks to their natural lack of multi photon-pair generation. Apart from telecom wavelength emission, integrability these sources ideally requires electrical operation deployment in compact systems the field. For multiplexing entangled photons with classical data traffic, emission O-band and tuneability nearest channel compliance coarse division standards (20...
The interference of photons emitted by dissimilar sources is an essential requirement for a wide range photonic quantum information applications. Many these applications are in communications and need to operate at standard telecommunication wavelengths minimize the impact photon losses be compatible with existing infrastructure. Here we demonstrate first time telecom-wavelength from InAs/GaAs dot single-photon source laser; important step towards such results good agreement theoretical...
The emission rate of entangled photons from cascaded few-level systems is limited by the dynamics radiative transitions. Here, we overcome continuous driving limit for a semiconductor quantum dot via an active reset cascade. We show theoretically and experimentally regime to enable generation photon pairs with higher fidelity than optimum continuously driven state. Finally, electrically generate average (79.5±1.1)% at record clock 1.15 GHz.Received 24 January 2020Revised 16 October...
Quantum networks are essential for realising distributed quantum computation and communication. Entangled photons a key resource, with applications such as distribution, relays, repeaters. All components integrated in network must be synchronised therefore comply certain clock frequency. In the most mature technology, rates have reached exceeded 1GHz. Here we show first electrically pulsed sub-Poissonian entangled photon source compatible existing fiber operating at this rate. The LED is...
We generate phase-controlled quantum beats in Raman scattering of single photons from a 40Ca+ ion, showing that Λ- and V-shaped level arrangements lead to interference absorption emission amplitudes, respectively.