Boron (B) and phosphorus (P) codoped silicon quantum dots (Si QDs) are dispersible in polar solvents without organic ligands and exhibit photoluminescence (PL) in the first (NIR-I) and second (NIR-II) near infrared (NIR) windows in biological tissues due to the optical transition from the donor to acceptor states. We studied the relationship between the PL wavelength, lifetime and quantum yield (QY) of the colloidal solution and the composition of the starting material for the preparation. We found that the PL lifetime and the QY are primarily determined by the composition, while the PL wavelength is mainly determined by the growth temperature. By optimizing the composition, we achieved QYs of 20.1% and 1.74% in the NIR-I and NIR-II regions, respectively, in methanol. We demonstrate the application for time-gated imaging in the NIR-II range.
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http://dx.doi.org/10.1039/c8nr03571g | DOI Listing |
Phys Rev Lett
December 2024
Laboratoire De Physique de l'École Normale Supérieure, ENS, PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75005 Paris, France.
Phys Rev Lett
December 2024
Key Laboratory of Materials Physics of Ministry of Education, School of Physics, Zhengzhou University, Zhengzhou 450001, China.
Sci Rep
January 2025
Departemant of Physics and Energy Engineering, Amirkabir University of Technology, Tehran, Iran.
With careful design and integration, microring resonators can serve as a promising foundation for developing compact and scalable sources of non-classical light for quantum information processing. However, the current design flow is hindered by computational challenges and a complex, high-dimensional parameter space with interdependent variables. In this work, we present a knowledge-integrated machine learning framework based on Bayesian Optimization for designing squeezed light sources using microring resonators.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, Korea.
Addressing and mitigating decoherence sources plays an essential role in the development of a scalable quantum computing system, which requires low gate errors to be consistently maintained throughout the circuit execution. While nuclear spin-free materials, such as isotopically purified silicon, exhibit intrinsically promising coherence properties for electron spin qubits, the omnipresent charge noise, when converted to magnetic noise under a strong magnetic field gradient, often hinders stable qubit operation within a time frame comparable to the data acquisition time. Here, we demonstrate both open- and closed-loop suppression techniques for the transduced noise in silicon spin qubits, resulting in a more than two-fold (ten-fold) improvement of the inhomogeneous coherence time (Rabi oscillation quality) that leads to a single-qubit gate fidelity of over 99.
View Article and Find Full Text PDFNat Commun
January 2025
TUM School of Natural Sciences, Department of Physics and Munich Center for Quantum Science and Technology (MCQST), Technical University of Munich, James-Franck-Str. 1, Garching, Germany.
Small registers of spin qubits in silicon can exhibit hour-long coherence times and exceeded error-correction thresholds. However, their connection to larger quantum processors is an outstanding challenge. To this end, spin qubits with optical interfaces offer key advantages: they can minimize the heat load and give access to modular quantum computing architectures that eliminate cross-talk and offer a large connectivity.
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