1,720,996 research outputs found
Cryogenically cooled 946nm Nd:YAG laser
No full textWe present the first multi-Watt demonstration of a diode pumped cryogenically cooled Nd:YAG operating on the 946nm, 4F3/2 to 4I9/2 transition. Preliminary results at LN temperature produced 3.8W of output power for 20.7W of incident pump power and a slope efficiency of 28%
Cryogenically cooled 946nm Nd:YAG laser
No full textWe present the first multi-Watt demonstration of a diode pumped cryogenically cooled neodymium-doped yttrium aluminum garnet (YAG) laser operating at 946 nm on the 4F3/2 to 4I9/2 transition. 3.8 W of continuous wave output power for 12.8 W of absorbed pump was obtained with a slope efficiency of 47%. In addition, we made an extensive characterization of the spectroscopic properties around the pump and laser wavelengths over the temperature range of 77 K to 300 K to find an increase of ~2.5 times for both the absorption and emission cross sections at the lowest temperature
Implications of the temperature dependence of Nd:YAG spectroscopic values for low temperature laser operation at 946nm
No full textDespite many papers in the literature on the spectroscopic properties of Nd-doped yttrium aluminium garnet (YAG), there does not appear to be a comprehensive study of the key absorption lines, nor emission lines that terminate in the ground state, i.e. around 900nm. We present our measurements of the key spectroscopic properties over the temperature range of 77K to 300K for Nd3+ ions doped in (YAG)
Development of a highly Flexible Incremental rolling process for the manufacture of a doubly curved sheet metal
No full textTemperature dependent Nd:KGW spectroscopy study
No full textWe report a high resolution spectroscopic characterisation of Nd:KGW as a function of temperature, over the range 80K - 450K. Measurements were made for the two dominant polarizations, with respect to the principal optical axes for the double tungstate crystal, namely E//Nm and E//Np for an Ng – cut crystal. Knowledge of the critical spectroscopic characteristics at various temperatures enables more accurate prediction of laser performance over a large range of possible operating conditions
Concentration dependence of energy transfer upconversion in Nd:YAG
No full textThe concentration dependence of energy transfer upconversion in Nd:YAG is investigated via the z-scan technique. The ETU coefficient is determined to increase from 35×10-18 cm3/s to 90×10-18 cm3/s when the concentration increases from 0.3 at.% to 1.1 at.%
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
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