| 1. |
- Bosma, Tom, et al.
(författare)
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Identification and tunable optical coherent control of transition-metal spins in silicon carbide
- 2018
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Ingår i: NPJ QUANTUM INFORMATION. - : SPRINGERNATURE. - 2056-6387. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Color centers in wide-bandgap semiconductors are attractive systems for quantum technologies since they can combine long-coherent electronic spin and bright optical properties. Several suitable centers have been identified, most famously the nitrogen-vacancy defect in diamond. However, integration in communication technology is hindered by the fact that their optical transitions lie outside telecom wavelength bands. Several transition-metal impurities in silicon carbide do emit at and near telecom wavelengths, but knowledge about their spin and optical properties is incomplete. We present all-optical identification and coherent control of molybdenum-impurity spins in silicon carbide with transitions at near-infrared wavelengths. Our results identify spin S= 1/2 for both the electronic ground and excited state, with highly anisotropic spin properties that we apply for implementing optical control of ground-state spin coherence. Our results show optical lifetimes of similar to 60 ns and inhomogeneous spin dephasing times of similar to 0.3 mu S, establishing relevance for quantum spin-photon interfacing.
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| 2. |
- Labrador-Páez, Lucia, et al.
(författare)
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pH dependence of water anomaly temperature investigated by Eu(III) cryptate luminescence
- 2020
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 412:1, s. 73-80
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Tidskriftsartikel (refereegranskat)abstract
- Although water has been extensively studied, not all of its unique properties have been fully understood. There is still controversy about the temperature at which hydrogen bonds are broken or weakened, producing the anomalous temperature dependence of many water properties. Different temperatures between 23 and 48 °C have been reported, but no study has scrutinized the reasons for this discrepancy. We suggest the determining role of pH in the alteration of the water anomaly temperature. We employed a luminescent europium trisbipyridine cryptate, which is highly sensitive to changes in the arrangement of water molecules and whose luminescence intensity and lifetime are not significantly influenced by variations over a broad pH range. Our results revealed an increase of the crossover temperature from circa 35 °C at pH 3.5 to circa 45 °C at pH 7 to 9, which explains the discrepancies of previous studies. The pH dependence of water anomaly temperature is an important property for a better understanding of water and water-based systems and applications.
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