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- Colóquio na área de Física é realizado amanhã (4)
Agenda de defesas Agenda de defesas
Colóquio na área de Física é realizado amanhã (4)
A promoção é do Programa de Pós-Graduação em Física (PPGF) da Universidade
O Colóquio do Curso de Inverno “From water to photons: turbulent behavior in fluids and random fiber lasers” será realizado amanhã (4), às 15h30, no Auditório do Departamento de Física do Centro de Ciências Exatas e da Natureza (CCEN) da UFPE, no Campus Recife. Os coloquialistas serão os professores Anderson Gomes e Giovani Vasconcelos, ambos do Departamento de Física da UFPE. O evento é aberto ao público e não é necessário fazer inscrição prévia. A promoção é do Programa de Pós-Graduação em Física (PPGF) da Universidade.
O colóquio, que será ministrado em português, é baseado em publicação recente de diversos autores [I. R. R. Gonzalez et al., Turbulence hierarchy in a random fibre laser, Nat. Commun. 8, 15731 (2017)].
Resumo em inglês:
Turbulence is a phenomenon that manifests itself in different environments and situations. It can arise in a natural event, including atmospheric, oceanic and biological, or can be a man created phenomena. In optics, turbulence has been man-created in a diversity of contexts, such as fiber lasers, solitons, Bose-Einstein condensates and nonlinear optics. In this colloquium, after a brief general introduction to the phenomena of turbulence, we will describe a recent collaborative work carried out by a group of students and their supervisors at the Physics Department, UFPE, in which, for the first time, turbulent behavior was experimentally observed in a random fiber laser and theoretically explained using a recently developed theoretical approach. A random fiber laser is a laser which is implemented in an optical fiber containing a gain medium, but does not have a conventional cavity formed by two fixed mirrors at their ends. In our case, the gain medium is an Erbium doped fiber, and the feedback is provided by a randomly inscribed fiber grating. That is why it is called a random fiber laser (RFL). By studying the intensity fluctuation at the RFL output as a function of excitation power, it was observed that it changes its behavior from a “quiet” non-turbulent Gaussian type intensity fluctuation below the RFL threshold, to a turbulent behavior described by a mixture of Meijer G-distributions with a stretched-exponential tail above threshold. A recently introduced hierarchical stochastic model, consistent with Kolmogorov’s theory of turbulence, theoretically explained the experimental results, as will be shown.
Mais informações
Programa de Pós-Graduação em Física da UFPE
(81) 2126.8449