Dr. Mustafa Gündogan
Profil
Forschungsthemen1
Verbesserte Atomare Quantenspeicher durch Dynamische Anpassung der Dichte
Quelle ↗Förderer: Einstein Postdoctoral Grant Zeitraum: 01/2026 - 12/2029 Projektleitung: Prof. Dr. Markus Krutzik, Dr. Mustafa Gündogan
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Publikationen25
Top 25 nach Zitationen — Quelle: OpenAlex (BAAI/bge-m3 embedded für Matching).
EPJ Quantum Technology · 348 Zitationen · DOI
Abstract We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity. KCL-PH-TH/2019-65, CERN-TH-2019-126
Physical review. B./Physical review. B · 286 Zitationen · DOI
Here, the authors tune the color of light emitted by single-atom imperfections (silicon vacancy color centers) inside a diamond. Such tunable imperfections can be networked together to build a quantum internet, where information can be securely exchanged using the laws of quantum physics. One problem is that all the centers need to emit at precisely the same color or wavelength. The authors overcome this challenge by placing color centers inside a diamond nanostring. By adjusting the tension in the string, atoms are stretched inside the crystal and tune the center to emit photons of a desired wavelength. The tuning method involves bending the string with a force controlled handily with an electrical voltage. A symphony of such tunable diamond strings could serve as the backbone of a future quantum internet.
IET Quantum Communication · 242 Zitationen · DOI
Abstract Concerted efforts are underway to establish an infrastructure for a global quantum Internet to realise a spectrum of quantum technologies. This will enable more precise sensors, secure communications, and faster data processing. Quantum communications are a front‐runner with quantum networks already implemented in several metropolitan areas. A number of recent proposals have modelled the use of space segments to overcome range limitations of purely terrestrial networks. Rapid progress in the design of quantum devices have enabled their deployment in space for in‐orbit demonstrations. We review developments in this emerging area of space‐based quantum technologies and provide a roadmap of key milestones towards a complete, global quantum networked landscape. Small satellites hold increasing promise to provide a cost effective coverage required to realise the quantum Internet. The state of art in small satellite missions is reviewed and the most current in‐field demonstrations of quantum cryptography are collated. The important challenges in space quantum technologies that must be overcome and recent efforts to mitigate their effects are summarised. A perspective on future developments that would improve the performance of space quantum communications is included. The authors conclude with a discussion on fundamental physics experiments that could take advantage of a global, space‐based quantum network.
Physical Review Letters · 205 Zitationen · DOI
We demonstrate the first solid-state spin-wave optical quantum memory with on-demand read-out. Using the full atomic frequency comb scheme in a Pr(3+):Y2SiO5 crystal, we store weak coherent pulses at the single-photon level with a signal-to-noise ratio >10. Narrow-band spectral filtering based on spectral hole burning in a second Pr(3+):Y2SiO5 crystal is used to filter out the excess noise created by control pulses to reach an unconditional noise level of (2.0±0.3)×10(-3) photons per pulse. We also report spin-wave storage of photonic time-bin qubits with conditional fidelities higher than achievable by a measure and prepare strategy, demonstrating that the spin-wave memory operates in the quantum regime. This makes our device the first demonstration of a quantum memory for time-bin qubits, with on-demand read-out of the stored quantum information. These results represent an important step for the use of solid-state quantum memories in scalable quantum networks.
Physical Review Letters · 202 Zitationen · DOI
Solid-state quantum emitters that couple coherent optical transitions to long-lived spin qubits are essential for quantum networks. Here we report on the spin and optical properties of individual tin-vacancy (SnV) centers in diamond nanostructures. Through cryogenic magneto-optical and spin spectroscopy, we verify the inversion-symmetric electronic structure of the SnV, identify spin-conserving and spin-flipping transitions, characterize transition linewidths, measure electron spin lifetimes, and evaluate the spin dephasing time. We find that the optical transitions are consistent with the radiative lifetime limit even in nanofabricated structures. The spin lifetime is phonon limited with an exponential temperature scaling leading to T_{1}>10 ms, and the coherence time, T_{2}^{*} reaches the nuclear spin-bath limit upon cooling to 2.9 K. These spin properties exceed those of other inversion-symmetric color centers for which similar values require millikelvin temperatures. With a combination of coherent optical transitions and long spin coherence without dilution refrigeration, the SnV is a promising candidate for feasable and scalable quantum networking applications.
Physical Review Letters · 142 Zitationen · DOI
We report on the quantum storage and retrieval of photonic polarization quantum bits onto and out of a solid state storage device. The qubits are implemented with weak coherent states at the single photon level, and are stored for a predetermined time of 500 ns in a praseodymium doped crystal with a storage and retrieval efficiency of 10%, using the atomic frequency comb scheme. We characterize the storage by using quantum state tomography, and find that the average conditional fidelity of the retrieved qubits exceeds 95% for a mean photon number μ=0.4. This is significantly higher than a classical benchmark, taking into account the poissonian statistics and finite memory efficiency, which proves that our crystal functions as a quantum storage device for polarization qubits. These results extend the storage capabilities of solid state quantum light matter interfaces to polarization encoding, which is widely used in quantum information science.
Physical Review Letters · 135 Zitationen · DOI
The silicon-vacancy center in diamond offers attractive opportunities in quantum photonics due to its favorable optical properties and optically addressable electronic spin. Here, we combine both to achieve all-optical coherent control of its spin states. We utilize this method to explore spin dephasing effects in an impurity-rich sample beyond the limit of phonon-induced decoherence: Employing Ramsey and Hahn-echo techniques at temperatures down to 40 mK we identify resonant coupling to a substitutional nitrogen spin bath as limiting decoherence source for the electron spin.
npj Quantum Information · 116 Zitationen · DOI
Abstract Global-scale quantum communication links will form the backbone of the quantum internet. However, exponential loss in optical fibres precludes any realistic application beyond few hundred kilometres. Quantum repeaters and space-based systems offer solutions to overcome this limitation. Here, we analyse the use of quantum memory (QM)-equipped satellites for quantum communication focussing on global range repeaters and memory-assisted (MA-) QKD, where QMs help increase the key rate by synchronising otherwise probabilistic detection events. We demonstrate that satellites equipped with QMs provide three orders of magnitude faster entanglement distribution rates than existing protocols based on fibre-based repeaters or space systems without QMs. We analyse how entanglement distribution performance depends on memory characteristics, determine benchmarks to assess the performance of different tasks and propose various architectures for light-matter interfaces. Our work provides a roadmap to realise unconditionally secure quantum communications over global distances with near-term technologies.
Physical Review Letters · 91 Zitationen · DOI
We report on experiments demonstrating the reversible mapping of heralded single photons to long-lived collective optical atomic excitations stored in a Pr3+:Y2SiO5 crystal. A cavity-enhanced spontaneous down-conversion source is employed to produce widely nondegenerate narrow-band (≈2 MHz) photon pairs. The idler photons, whose frequency is compatible with telecommunication optical fibers, are used to herald the creation of the signal photons, compatible with the Pr3+ transition. The signal photons are stored and retrieved using the atomic frequency comb protocol. We demonstrate storage times up to 4.5 μs while preserving nonclassical correlations between the heralding and the retrieved photon. This is more than 20 times longer than in previous realizations in solid state devices, and implemented in a system ideally suited for the extension to spin-wave storage.
New Journal of Physics · 76 Zitationen · DOI
<p>We report on the coherent and multi-temporal mode storage of light using the full atomic frequency comb memory scheme. The scheme involves the transfer of optical atomic excitations in Pr<sup>3+</sup>:Y<sub>2</sub>SiO<sub>5</sub> to spin waves in hyperfine levels using strong single-frequency transfer pulses. Using this scheme, a total of five temporal modes are stored and recalled on-demand from the memory. The coherence of the storage and retrieval is characterized using a time-bin interference measurement resulting in visibilities higher than 80%, independent of the storage time. This coherent and multimode spin-wave memory is promising as a quantum memory for light.</p>
Bristol Research (University of Bristol) · 68 Zitationen · DOI
We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies.
Communications Physics · 53 Zitationen · DOI
Abstract A global quantum repeater network involving satellite-based links is likely to have advantages over fiber-based networks in terms of long-distance communication, since the photon losses in vacuum scale only polynomially with the distance – compared to the exponential losses in optical fibers. To simulate the performance of such networks, we have introduced a scheme of large-scale event-based Monte Carlo simulation of quantum repeaters with multiple memories that can faithfully represent loss and imperfections in these memories. In this work, we identify the quantum key distribution rates achievable in various satellite and ground station geometries for feasible experimental parameters. The power and flexibility of the simulation toolbox allows us to explore various strategies and parameters, some of which only arise in these more complex, multi-satellite repeater scenarios. As a primary result, we conclude that key rates in the kHz range are reasonably attainable for intercontinental quantum communication with three satellites, only one of which carries a quantum memory.
Advanced Quantum Technologies · 21 Zitationen · DOI
Abstract Modern quantum technologies have matured such that they can now be used in space applications, e.g., long‐distance quantum communication. Here, the design of a compact true single photon source is presented that can enhance the secure data rates in satellite‐based quantum key distribution scenarios compared to conventional laser‐based light sources. The quantum light source is a fluorescent color center in hexagonal boron nitride. The emitter is off‐resonantly excited by a diode laser and directly coupled to an integrated photonic processor that routes the photons to different experiments performed directly on‐chip: i) the characterization of the single photon source and ii) testing a fundamental postulate of quantum mechanics, namely the relation of the probability density and the wave function (known as Born's rule). The described payload is currently being integrated into a 3U CubeSat and scheduled to launch in 2024 into low Earth orbit. Therefore the feasibility of true single photon sources and reconfigurable photonic circuits in space can be evaluated. This provides a promising route toward a high‐speed quantum network.
Oxford University Research Archive (ORA) (University of Oxford) · 21 Zitationen · DOI
Quantum correlations between long-lived quantum memories and telecom photons that can propagate with low loss in optical fibers are an essential resource for the realization of large-scale quantum information networks. Significant progress has been realized in this direction with atomic and solid-state systems. Here, we demonstrate quantum correlations between a telecom photon and a multimode ondemand solid state quantum memory. This is achieved by mapping a correlated single photon onto a spin collective excitation in a Pr 3+ :Y 2 SiO 5 crystal for a controllable time. The stored single photons are generated by cavity-enhanced spontaneous parametric down-conversion and heralded by their partner photons at telecom wavelength. These results represent the first demonstration of a multimode on-demand solid state quantum memory for external quantum states of light. They provide an important resource for quantum repeaters and pave the way for the implementation of quantum information networks with distant solid state quantum nodes.
Optica Quantum · 19 Zitationen · DOI
Global-scale quantum networking faces significant technical and scientific obstacles. Quantum repeaters (QRs) have been proposed to overcome the inherent direct transmission range limit through optical fiber. However, QRs are typically limited to a total distance of a few thousand kilometers and/or require extensive hardware overhead. Recent proposals suggest that strings of space-borne QRs with on-board quantum memories (QMs) are able to provide global coverage. Here, we propose an alternative to such repeater constellations using a single satellite with two QMs that effectively acts as a time-delayed version of a single QR node. By physically transporting stored qubits, our protocol improves long-distance entanglement distribution with reduced system complexity over previous proposals. We estimate the amount of secure key in the finite block regime and demonstrate an improvement of at least three orders of magnitude over prior single-satellite methods that rely on a single QM, while simultaneously reducing the necessary memory capacity similarly. We propose an experimental platform to realize this scheme based on rare-earth ion doped crystals with appropriate performance parameters. By exploiting recent advances in quantum memory lifetimes, we are able to significantly reduce system complexity while achieving high key rates, bringing global quantum networking closer to implementation.
Strathprints: The University of Strathclyde institutional repository (University of Strathclyde) · 16 Zitationen · DOI
Global scale quantum communication links will form the backbone of the quantum internet. However, exponential loss in optical fibres precludes any realistic application beyond few hundred kilometres. Quantum repeaters and space-based systems offer to overcome this limitation. Here, we analyse the use of quantum memory (QM)-equipped satellites for quantum communication focussing on global range repeaters and Measurement-Device-Independent (MDI) QKD. We demonstrate that satellites equipped with QMs provide three orders of magnitude faster entanglement distribution rates than existing protocols based on fibre-based repeaters or space systems without QMs. We analyse how entanglement distribution performance depends on memory characteristics, determine benchmarks to assess performance of different tasks, and propose various architectures for light-matter interfaces. Our work provides a practical roadmap to realise unconditionally secure quantum communications over global distances with current technologies.
Entanglement dynamics of photon pairs and quantum memories in the gravitational field of the earth
2024Quantum · 10 Zitationen · DOI
We investigate the effect of entanglement dynamics due to gravity – the basis of a mechanism of universal decoherence – for photonic states and quantum memories in Mach-Zehnder and Hong-Ou-Mandel interferometry setups in the gravitational field of the earth. We show that chances are good to witness the effect with near-future technology in Hong-Ou-Mandel interferometry. This would represent an experimental test of theoretical modeling combining a multi-particle effect predicted by the quantum theory of light and an effect predicted by general relativity. Our article represents the first analysis of relativistic gravitational effects on space-based quantum memories which are expected to be an important ingredient for global quantum communication networks.
Physical Review Research · 10 Zitationen · DOI
Bose-Einstein condensates are a promising platform for optical quantum memories but suffer from several decoherence mechanisms, leading to short memory lifetimes. While some of these decoherence effects can be mitigated by conventional methods, density-dependent atom-atom collisions ultimately set the upper limit of the quantum memory lifetime to timescales of seconds in trapped Bose-Einstein condensates. We propose a quantum memory technique that utilizes microgravity as a resource to minimize such density-dependent effects. We show that by using optical atom lenses to collimate and refocus the freely expanding atomic ensembles, in a semi-ideal environment, the expected memory lifetime is only limited by the quality of the background vacuum. We anticipate that this method can be experimentally demonstrated in Earth-bound microgravity platforms or space missions, eventually leading to storage times of minutes and unprecedented time-bandwidth products of ${10}^{10}$.
Strathprints: The University of Strathclyde institutional repository (University of Strathclyde) · 8 Zitationen · DOI
It has recently been theoretically shown that Quantum Memories (QM) could enable truly global quantum networking when deployed in space thereby surpassing the limited range of land-based quantum repeaters. Furthermore, QM in space could enable novel protocols and long-range entanglement and teleportation applications suitable for Deep-Space links and extended scenarios for fundamental physics tests. In this white paper we will make the case for the importance of deploying QMs to space, and also discuss the major technical milestones and development stages that will need to be considered.
Physical review. A/Physical review, A · 7 Zitationen · DOI
Quantum memories promise to enable global quantum repeater networks. For field applications, alkali-metal vapors constitute an exceptional storage platform, as neither cryogenics, nor strong magnetic fields are required. We demonstrate a technologically simple, in principle satellite-suited quantum memory based on electromagnetically induced transparency on the cesium $D1$ line, and focus on the tradeoff between end-to-end efficiency and signal-to-noise ratio, both being key parameters in applications. For coherent pulses containing one photon on average, we achieve storage and retrieval with end-to-end efficiencies of ${\ensuremath{\eta}}_{\text{e2e}}=13(2)%$, which correspond to internal memory efficiencies of ${\ensuremath{\eta}}_{\text{mem}}=33(1)%$. Simultaneously, we achieve a noise level corresponding to ${\ensuremath{\mu}}_{1}=0.07(2)$ signal photons. This noise is dominated by spontaneous Raman scattering, with contributions from fluorescence. Four-wave mixing noise is negligible, allowing for further minimization of the total noise level.
Physical Review Applied · 6 Zitationen · DOI
We present the implementation and performance analysis of a portable rack-mounted stand-alone warm-vapor quantum memory system that also includes the laser package, control electronics, and data-processing hardware. The optical memory is based on long-lived hyperfine ground states of cesium, which are connected to an excited state via the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:msub><a:mi>D</a:mi><a:mn>1</a:mn></a:msub></a:math> line at 895 nm in a <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><d:mi mathvariant="normal">Λ</d:mi></d:math>-configuration. The memory is operated with weak coherent pulses containing on average <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><h:mo><</h:mo><h:mn>1</h:mn></h:math> photons per pulse. The long-term stability of the memory efficiency and storage fidelity is demonstrated at the single-photon level together with operation in a nonlaboratory environment.
arXiv (Cornell University) · 5 Zitationen
International Journal of Optomechatronics · 4 Zitationen · DOI
Liquid microdroplets are attractive as optical microcavities with tunable resonances for applications in quantum optics and biological sensing, owing to their flexible nature and spherical shape. Salt-water microdroplets can be used in such experiments while standing on a superhydrophobic surface that preserves their spherical geometry. Here, we report how the photothermal effect enables continuous tuning or locking of the whispering gallery mode (WGM) spectrum and size of salt-water microdroplets on a superhydrophobic surface. Local heating by an infrared laser focused at the center of a microdroplet causes it to depart from its equilibrium size, shifting the WGM spectrum. This photothermal tuning effect is fully reversible and can be used to tune the microdroplet radius with a precision reaching 1 Å. We combine this effect with fluorescence excitation spectroscopy using a fixed wavelength laser to measure Q-factors of up to ∼105. Conversely, focusing the heating laser to the microdroplet rim reveals absorption resonances, leading to a hysteretic behavior when cycling the laser power. We show that this behavior can be used to lock the size of a microdroplet and make it exhibit optical bistability. WGM resonances of locked microdroplets are probed using a tunable laser, showing a spectral locking precision reaching <0.01 nm over tens of minutes. These results indicate that the wavelength stability and positioning challenges inherent to liquid microdroplets in air can be overcome, providing an easily tunable and lockable alternative to solid optical microcavities and making them potential candidates for studies in cavity optomechanics.
3 Zitationen · DOI
Optical quantum memories (QMs) are one of the fundamental building blocks in quantum information science (QIS). They might find important use in quantum communication and computation applications. Rare-earth ions (REIs) have been investigated for decades for their optical properties. They exhibit excellent coherence properties when cooled down to cryogenic temperatures. Not surprisingly, they emerged as a promising candidate for use in QIS as QMs. In this thesis, we investigated the quantum storage of photonic qubits in a Pr3+ :Y2SiO5 (PrYSO) crystal for potential use in quantum communication and networking applications. We started by constructing the experimental setup and the laser system from scratch as our research group had just been established at the beginning of this PhD study. First experiments included spectroscopy of the PrYSO system in order to identify the electronic transitions that are suitable for the QM experiments. We used the atomic frequency comb (AFC) memory protocol in all the experiments presented in this thesis. We also developed complex pulse sequences that are necessary for the optical preparation of an AFC. As a first experiment, we demonstrated the storage of photonic polarization qubits encoded in weak coherent states in the excited states of Pr3+ ions for a predetermined storage time of 500 ns. This had not been achieved previously due to the polarization dependent absorption of the material. We achieved average storage fidelities of ~95% which surpass the best achievable value with a measure and prepare strategy, thus proving the quantum character of our interface. Nevertheless, in order to be implemented in realistic quantum networking architectures, a QM should have the capability of on-demand retrieval of the stored information. As a first step towards this goal, our next experiment concerned the transfer of the input pulses to and from the long-lived hyperfine ground levels of Pr3+ ions, albeit with bright pulses. Furthermore, by performing time-bin interference experiments, we demonstrated that the coherence is preserved during the storage, transfer and retrieval processes. Temporal multimode storage in the spin-states up to 5 modes was also shown. Finally, in the last part of this thesis we demonstrated a solid-state spinwave quantum memory, with qubits encoded in weak coherent states at the single photon level. Storing and retrieving single-photon level fields in the ground levels of the PrYSO system is challenging as the strong control pulses and the weak input pulse to be stored in the memory are separated by only 10:2 MHz. The control pulses create noise, mostly as free-induction decay, fluorescence and scattering off the optical surfaces. In order to circumvent this problem we employed narrow-band spectral, temporal and spatial filtering. By using spectral-hole burning based narrow band filter created in a second PrYSO crystal, we could achieve signal-to-noise ratio (SNR) > 10 for input pulses with mean photon number of around 1. The high SNR we achieved allowed us to store and recall time-bin qubits with conditional fidelities again higher than that is possible with a measure and prepare strategy. This experiments also represents the first demonstration of a quantum memory for time-bin qubits with on demand read-out of the stored quantum information. The results presented in this thesis fill an important gap in the field of solid-state quantum memories and open the way for the long-lived storage of non-classical states of light. They further strengthen the position of REI based systems in QIS, specifically as nodes in scalable quantum network architectures. Les memòries quàntiques òptiques (MQs) son un dels elements fonamentals en la ciència de la informació quàntica (CIQ). El seu ús podria ser important en aplicacions relacionades amb la comunicació i la computació quàntiques. Els ions de terres rares (ITRs) han sigut investigats durant dècades per les seves propietats òptiques. Exhibeixen excel·lents propietats de coherència quan es refreden a temperatures criogèniques. Per tant, no es sorprenent que hagin emergit com a candidats per ser usats en la CIQ com a MQs. En aquesta tesis, hem investigat l'emmagatzematge quàntic de qubits fotònics en un cristall de Pr3+:Y2SiO5 (PrYSO) per al seu possible ús en aplicacions relacionades amb xarxes d'informació quàntiques. Vam començar construint el dispositiu experimental i sistemes làser des de zero, ja que el nostre grup de recerca acabava de néixer. Els primers experiments van incloure espectroscòpia del sistema de PrYSO per identificar les transicions electròniques més apropiades per als següents experiments de MQs. En tots els experiments vam utilitzar el protocol de memòria basat en una pinta de freqüències atòmiques (PFA). També vam desenvolupar complexes seqüències de polsos, necessàries per a la preparació òptica d'una PFA. En el primer experiment vam demostrar l'emmagatzematge de qubits fotònics de polarització codificats en estats coherents febles. Aquest emmagatzematge es va dur a terme en els estats excitats dels ions Pr3+ durant un temps d'emmagatzematge predeterminat de 500 ns. Aquesta fita no s'havia assolit abans degut a que l'absorció òptica del material depèn de la polarització llum. Vam aconseguir fidelitats d'emmagatzematge d'un 95% de mitjana les quals sobrepassen el millor valor que es pot aconseguir amb una estratègia de mesura i preparació provant per tant el caràcter quàntic de la nostra interfície. Per poder-se implementar de manera realista en xarxes quàntiques, una MQ hauria de tenir la capacitat de recuperar la informació en-demanda (en el moment que es desitgi). Com a primer pas, el nostre següent experiment va involucrar la transferència dels polsos d'entrada cap a i des de els nivells fonamentals hiperfins i longeus dels ions Pr3+, mitjançant polsos brillants. A més, duent a terme experiments d'interferència, vam demostrar que la coherència es preserva durant els processos d'emmagatzematge, transferència i recuperació. També vam demostrar l'emmagatzematge temporalment multimodal en els estats d'espín, de fins a 5 modes. En l'última part d'aquesta tesis vam demostrar una memòria quàntica d'estat sòlid basada en ones d'espín, amb qubits codificats en estats coherents febles al nivell d'intensitat de fotons individuals. Emmagatzemar i recuperar camps òptics al nivell de fotons individuals en estats fonamentals del sistema PrYSO és exigent perquè els potents polsos de control i el polsos dèbils d'entrada que s'emmagatzemen a la memòria estan separats per només 10.2 MHz. Els polsos de control creen soroll, la majoria consistent en decaïment de lliure inducció, fluorescència i dispersió en les superfícies òptiques. Per resoldre aquest problema vam utilitzar filtratge estret de banda en freqüència i també filtratges temporal i espacial. Utilitzant un filtre estret de banda basat el la crema de forats espectrals en un segon cristall de PrYSO, vam poder aconseguir una relació senyal soroll (RSS) > 10 per a polsos d'entrada amb un número mitjà de fotons al voltant de 1. L'alta RSS que vam aconseguir ens va permetre emmagatzemar i recuperar qubits de inteval-de-temps amb fidelitats condicionals més altes una altra vegada que el que és possible amb l'estratègia de mesura i preparació. Els resultats presentats omplen un buit important en el camp de les memòries quàntiques d'estat sòlid i obren la porta a l'emmagatzematge de llarga durada d'estats de llum no-clàssics. A més, enforteixen la posició dels sistemes de IQ basats en ITR, específicament com a nodes en arquitectures de xarxes quàntiques.
Prolonged Raman lasing in size-stabilized salt-water microdroplets on a superhydrophobic surface
2010Optics Letters · 3 Zitationen · DOI
We demonstrate prolonged Raman lasing from individual salt-water microdroplets with 10-20 microm diameters located on a superhydrophobic surface. The mechanism is based on the absorption heating of a 1064 nm cw IR laser and the resonant heating of a 532 nm pulsed, pump laser. A clear hysteresis is observed in the lasing intensity as the droplet size is photothermally tuned by the IR laser, indicating a self-stabilization mechanism due to the resonant absorption of the pump laser. Using this mechanism, Raman lasing near 650 nm is sustained for up to 25 min, approximately 1000 times longer than lasing durations reported in previous studies.
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- Name
- Dr. Mustafa Gündogan
- Titel
- Dr.
- Fakultät
- Mathematisch-Naturwissenschaftliche Fakultät
- Institut
- Institut für Physik
- Arbeitsgruppe
- Integrierte Quantensensoren
- Telefon
- +49 30 2093-4907
- HU-FIS-Profil
- Quelle ↗
- Zuletzt gescrapt
- 26.4.2026, 01:05:32