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《无机发光材料物理与化学》课程学术讲座之7-8讲
更新日期:2018-11-23  
标题:《无机发光材料物理与化学》课程学术讲座之7-8讲:Electronic and Hyperfine Structure of Rare-Earth Ions in Y2SiO5
主讲人:Mike Reid教授
单位:新西兰Canterbury大学物理和化学学院
时间:2018年11月29日9:30AM
地点:纳米楼一楼报告厅   

Abstract:  

One of the challenges for practical quantum-information applications, such as encryption and computation, is the preservation of quantum coherence. Quantum coherence may be stored by making use of the nuclear spins of rare-earth (lanthanide) ions, which are coupled to the electronic states via the hyperfine interaction. Storage of quantum coherence for over six hours using magnetic-hyperfine levels of Eu3+ ions in YSO has been achieved by using the ZEFOZ (ZEro First-Order Zeeman) approach, where the direction and magnitude of an applied magnetic field is adjusted to yield a radio-frequency transition that has no first-order dependence on magnetic field variations, and is thus insensitive to magnetic field inhomogeneity. 

 

Applications development, such as the location of ZEFOZ points, requires accurate modelling of hyperfine and magnetic interactions, which is usually done using a spin Hamiltonian. Spin-Hamiltonian parameters are not transferrable to other electronic states, or to other ions, so each electronic state requires a different spin Hamiltonian. We aim to model electronic and hyperfine energy levels consistently across the rare-earth series using a "crystal field" model. This will enable more efficient investigation of candidates for applications. The lack of symmetry in YSO makes a conventional crystal-field approach impossible. However, by adding magnetic and hyperfine data to remove ambiguities, we have recently shown that it is possible to perform accurate fits for Er3+. We are now investigating other ions, including Nd3+ and Sm3+, to demonstrate that we can transfer the crystal-field parameters from Er3+ and identify the two different crystallographic sites using Zeeman and laser spectroscopy.