08 Fakultät Mathematik und Physik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/9
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Item Open Access Integrated optoelectronic devices using lab‐on‐fiber technology(2022) Ricciardi, Armando; Zimmer, Michael; Witz, Norbert; Micco, Alberto; Piccirillo, Federica; Giaquinto, Martino; Kaschel, Mathias; Burghartz, Joachim; Jetter, Michael; Michler, Peter; Cusano, Andrea; Portalupi, Simone LucaSilica fibers are nowadays cornerstones in several technological implementations from long‐distance communication, to sensing applications in many scenarios. To further enlarge the functionalities, the compactness, and the performances of fiber‐based devices, one needs to reliably integrate small‐footprint components such as sensors, light sources, and detectors onto single optical fiber substrates. Here, a novel proof of concept is presented to deterministically integrate optoelectronic chips onto the facet of an optical fiber, further implementing the electrical contacting between the chip and fiber itself. The CMOS‐compatible procedure is based on a suitable combination of metal deposition, laser machining, and micromanipulation, directly applied onto the fiber tip. The proposed method is validated by transferring, aligning, and bonding a quantum‐well based laser on the core of a multimode optical fiber. The successful monolithic device integration on fiber shows simultaneously electrical contacting between the laser and the ferrule, and 20% light in‐coupling in the fiber. These results pave new ways to develop the next generation of optoelectronic systems on fiber. The technological approach will set a new relevant milestone along the lab‐on‐fiber roadmap, opening new avenues for a novel class of integrated optoelectronic fiber platforms, featuring unrivaled miniaturization, compactness, and performances levels, designed for specific applications.Item Open Access Bright source of Purcell‐enhanced, triggered, single photons in the telecom C‐band(2023) Nawrath, Cornelius; Joos, Raphael; Kolatschek, Sascha; Bauer, Stephanie; Pruy, Pascal; Hornung, Florian; Fischer, Julius; Huang, Jiasheng; Vijayan, Ponraj; Sittig, Robert; Jetter, Michael; Portalupi, Simone Luca; Michler, PeterSeveral emission features mark semiconductor quantum dots as promising non-classical light sources for prospective quantum implementations. For long-distance transmission and Si-based on-chip processing, the possibility to match the telecom C-band is decisive, while source brightness and high single-photon purity are key features in virtually any quantum implementation. An InAs/InGaAs/GaAs quantum dot emitting in the telecom C-band coupled to a circular Bragg grating is presented here. This cavity structure stands out due to its high broadband collection efficiency and high attainable Purcell factors. Here, simultaneously high brightness with a fiber-coupled single-photon count rate of 13.9 MHz for an excitation repetition rate of 228 MHz (first-lens single-photon collection efficiency ≈17% for NA = 0.6), while maintaining a low multi-photon contribution of g(2)(0) = 0.0052 is demonstrated. Moreover, the compatibility with temperatures of up to 40 K attainable with compact cryo coolers, further underlines the suitability for out-of-the-lab implementations.Item Open Access Observation of ultrafast interfacial Meitner-Auger energy transfer in a Van der Waals heterostructure(2023) Dong, Shuo; Beaulieu, Samuel; Selig, Malte; Rosenzweig, Philipp; Christiansen, Dominik; Pincelli, Tommaso; Dendzik, Maciej; Ziegler, Jonas D.; Maklar, Julian; Xian, R. Patrick; Neef, Alexander; Mohammed, Avaise; Schulz, Armin; Stadler, Mona; Jetter, Michael; Michler, Peter; Taniguchi, Takashi; Watanabe, Kenji; Takagi, Hidenori; Starke, Ulrich; Chernikov, Alexey; Wolf, Martin; Nakamura, Hiro; Knorr, Andreas; Rettig, Laurenz; Ernstorfer, RalphAtomically thin layered van der Waals heterostructures feature exotic and emergent optoelectronic properties. With growing interest in these novel quantum materials, the microscopic understanding of fundamental interfacial coupling mechanisms is of capital importance. Here, using multidimensional photoemission spectroscopy, we provide a layer- and momentum-resolved view on ultrafast interlayer electron and energy transfer in a monolayer-WSe2/graphene heterostructure. Depending on the nature of the optically prepared state, we find the different dominating transfer mechanisms: while electron injection from graphene to WSe2 is observed after photoexcitation of quasi-free hot carriers in the graphene layer, we establish an interfacial Meitner-Auger energy transfer process following the excitation of excitons in WSe2. By analysing the time-energy-momentum distributions of excited-state carriers with a rate-equation model, we distinguish these two types of interfacial dynamics and identify the ultrafast conversion of excitons in WSe2 to valence band transitions in graphene. Microscopic calculations find interfacial dipole-monopole coupling underlying the Meitner-Auger energy transfer to dominate over conventional Förster- and Dexter-type interactions, in agreement with the experimental observations. The energy transfer mechanism revealed here might enable new hot-carrier-based device concepts with van der Waals heterostructures.Item Open Access Optical charge injection and coherent control of a quantum-dot spin-qubit emitting at telecom wavelengths(2022) Dusanowski, Łukasz; Nawrath, Cornelius; Portalupi, Simone L.; Jetter, Michael; Huber, Tobias; Klembt, Sebastian; Michler, Peter; Höfling, SvenSolid-state quantum emitters with manipulable spin-qubits are promising platforms for quantum communication applications. Although such light-matter interfaces could be realized in many systems only a few allow for light emission in the telecom bands necessary for long-distance quantum networks. Here, we propose and implement an optically active solid-state spin-qubit based on a hole confined in a single InAs/GaAs quantum dot grown on an InGaAs metamorphic buffer layer emitting photons in the C-band. We lift the hole spin-degeneracy using an external magnetic field and demonstrate hole injection, initialization, read-out and complete coherent control using picosecond optical pulses. These results showcase a solid-state spin-qubit platform compatible with preexisting optical fiber networks.Item Open Access High-rate intercity quantum key distribution with a semiconductor single-photon source(2024) Yang, Jingzhong; Jiang, Zenghui; Benthin, Frederik; Hanel, Joscha; Fandrich, Tom; Joos, Raphael; Bauer, Stephanie; Kolatschek, Sascha; Hreibi, Ali; Rugeramigabo, Eddy Patrick; Jetter, Michael; Portalupi, Simone Luca; Zopf, Michael; Michler, Peter; Kück, Stefan; Ding, FeiQuantum key distribution (QKD) enables the transmission of information that is secure against general attacks by eavesdroppers. The use of on-demand quantum light sources in QKD protocols is expected to help improve security and maximum tolerable loss. Semiconductor quantum dots (QDs) are a promising building block for quantum communication applications because of the deterministic emission of single photons with high brightness and low multiphoton contribution. Here we report on the first intercity QKD experiment using a bright deterministic single photon source. A BB84 protocol based on polarisation encoding is realised using the high-rate single photons in the telecommunication C-band emitted from a semiconductor QD embedded in a circular Bragg grating structure. Utilising the 79 km long link with 25.49 dB loss (equivalent to 130 km for the direct-connected optical fibre) between the German cities of Hannover and Braunschweig, a record-high secret key bits per pulse of 4.8 × 10 -5 with an average quantum bit error ratio of ~ 0.65% are demonstrated. An asymptotic maximum tolerable loss of 28.11 dB is found, corresponding to a length of 144 km of standard telecommunication fibre. Deterministic semiconductor sources therefore challenge state-of-the-art QKD protocols and have the potential to excel in measurement device independent protocols and quantum repeater applications.