1,721,003 research outputs found

    110W 790nm pumped 1908nm thulium fibre laser

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    We describe the highest power 790nm pumped 1908nm thulium fibre laser reported with an output of 110W and a resolution limited linewidth of 0.5nm.Shayne Bennetts, Alexander Hemming Alan Davidson and David G Lancaste

    Multiple-watt Tm3+, Ho3+-co-doped silica fibre laser tunable across both dopant transitions

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    We have obtained tunable laser emission across both Tm3+ and Ho3+ transitions in a 0.79-mum pumped Tm3+, Ho3+-co-doped silica fibre laser. For a 2.3 m fibre a 1920-2125 nm tuning range was measured with 3.6 W maximum power.Alexander Sabella, Alexander Hemming, Shayne Bennetts, Stuart D Jackson and David G Lancaste

    High power cryogenic Ho:YAG laser

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    We have improved significantly the brightness of cryogenic Ho:YAG, reporting up to 65 W output power with a beam quality of M² <1.3 and a slope efficiency of 71%. The laser emission was ~2 nm wide and centered at 2097.5 nm. This result demonstrates the scalability of both the narrow-line thulium fibre pump laser and the cryogenic laser head.Miftar Ganija, Alexander Hemming, Nikita Simakov, Keiron Boyd, John Haub, Peter Veitch and Jesper Munc

    Q-switched Cryogenic Ho:YAG Laser

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    OSA Technical Digest (online) (Optical Society of America, 2018), paper SM4N.3. From the session Laser Materials (SM4N)We describe the first power scalable, Q-switched, cryogenically cooled, resonantly pumped, Ho:YAG laser oscillator. The output energy was extracted from a confocal resonator with a single-pass pump geometry. Pulsed operation at higher average powers will be reported.Miftar Ganija, Alexander Hemming, Nikita Simakov, Neil Carmody, Peter Veitch, John Haub and Jesper Munc

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship

    A linearly polarised, pulsed Ho-doped fiber laser

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    Abstract not availableSophie Hollitt, Nikita Simakov, Alexander Hemming, John Haub and Adrian Carte

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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