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The sensitization of lanthanide complexes in the visible region is of particular interest for practical applications such as labeling, biological analysis and optoelectronics. A visible-light sensitized Er3+complex based on the use of a highly conjugated ß-diketonate (1, 3-di(2-naphthyl)-1, 3-propanedione, Hdnm) and 5-nitro-1, 10-phenanthroline (5NO2phen) as an ancillary ligand, [Er(dnm)3(5NO2phen)], has been synthesized, fully characterized and its photophysical properties have been investigated. Suitably expanded p-conjugation in the complex molecule makes the excitation window red-shifted to the visible region (up to 550 nm). Efficient energy transfer by antenna effect results in 1.53 µm emission from the Er3+ion.

In this paper we report the work that jeKnowledge (Júnior Empresa da Faculdade de Ciências e Tecnologias da Universidade de Coimbra), a student-led initiative, has done in the ‘jeKnowledge academy’ courses to actively engage Portuguese high-school students in STEM education through hands-on projects based on the low-cost Arduino platform. F2F activities, based on a peer-assisted learning strategy, were complemented with tutorials and more advanced project suggestions in a blog. Pre and post surveys on students'' attitudes towards programming and peer-coaching were administered to pre-university and first year college participants, finding an overall increase in the Likert scale for all the programming-related constructs under study (confidence, interest, gender, usefulness and professional) after the introductory course. As regards the peer-based learning approach, younger students seemed to be more eager to be taught in a less formal way than their older counterparts. The course resulted in high degrees of satisfaction for both the student tutors and their tutees.

This paper considers right-invariant and controllable driftless quantum systems with state X(t) evolving on the unitary group U(n) and m inputs. The T-sampling stabilization problem is introduced and solved: given any initial condition X(0) any goal state Xg find a feedback law such that X(jT) converges to Xg as the integer j tends to infinity. The purpose is to generate arbitrary quantum gates corresponding to Xg. This is achieved by the tracking of T-periodic reference trajectories that pass by Xg using the framework of Coron's Return Method. The T-periodic reference trajectories are generated by applying open-loop controls that are a sum of a finite number M of odd T-periodic function whose amplitudes are parameterized by a vector. The main result establishes that, for M big enough, X(jT) exponentially converges towards Xg for almost all fixed amplitude vectors, with explicit and completely constructive control laws. This paper also establishes a stochastic version of this deterministic control law. The key idea is to randomly choose a different amplitude vector at each sampling time jT, and keeping it fixed until the next sampling time (j+1)T. It is also shown that X(jT) exponentially converges towards Xg almost surely. Simulation results have indicated that the convergence speed may be significantly improved with such stochastic technique. This is illustrated in the generation of the C--NOT quantum logic gate on U(4)., 23 pages, 4 figures, submitted

International audience; This work treats the problem of generating any desired goal propagator for a driftless quantum system that evolves on the unitary group U(n). The physical relevance of such control problem is the realization of arbitrary quantum gates in quantum computers. Assuming only the controllability of the system, the paper constructs explicit stochastic control laws that assure global asymptotic convergence of the propagator of the system towards the goal propagator. The purpose of introducing a stochastic behaviour in the controls is to speed up convergence. The control strategy can be rigorously proved based on Lyapunov feedback and stochastic techniques. The controls laws rely on a reference trajectory that crosses the desired goal propagator in a time-periodic fashion and such that its corresponding linearised system generates the Lie algebra u(n). Their existence is ensured by the ReturnMethod of Coron, and standard Fourier series results allows them to be explicitly constructed.

International audience; In a previous work, the authors have introduced and treated the periodic motion planning problem for right-invariant driftless systems that evolve on SU(n), which in turn corresponds to an approximate motion planning control problem. Although the only assumption was the controllability of the system, the control laws are not explicitly known in general. By using analogous Lyapunov-like control techniques that were developed in that work, this paper complements its results and proves that if the system satisfies a more restrictive form of controllability, then the control laws are given by explicit and analytical expressions. Simulation results are presented for n = 4 and the generation of the C-NOT (Controlled-NOT) quantum logic gate.