1,720,967 research outputs found
High pulse energy picosecond MgO:PPLN optical parametric oscillator using a single-mode fiber for signal feedback
No full textWe demonstrate a high-pulse-energy, synchronously-pumped (7.19MHz), 100ps, widely tunable MgO:PPLN OPO providing 0.49µJ pulses at 1.5µm and 0.19µJ pulses at 3.6µm. A single-mode fiber is employed in the OPO to keep the 42m-long cavity compact
Laser-induced crystalline optical waveguide on glass fibre
No full textWe report for the first time the fabrication of a novel glass ribbon fibre with laser-induced single (or quasi-single) crystalline (La,Yb)BGeO5 optical waveguide
200W gain-switched-diode-seeded single-polarization narrow linewidth all-fiber picosecond MOPA
No full textWe report a fully fiberized, single-polarization, gain-switched, diode-seeded fiber MOPA delivering 28ps pulses at a repetition frequency of 214MHz with 200W of average output power and up to 0.93µJ pulse energy
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
Rapidly tunable, wavelength agile, visible fiber based light source exploiting Raman scattering of multi-step pulses
No full textSynchronously pumped tunable Raman laser in the visible pumped by an all-fiber PM MOPA at 1060nm
No full textHigh-energy diode-seeded nanosecond 2µm fiber MOPA systems incorporating active pulse shaping
No full textWe report on high-energy nanosecond-pulsed fiber master oscillator power amplifier (MOPA) systems seeded by semiconductor laser diodes at 2µm incorporating arbitrary pulse-shaping capabilities. Two MOPA systems, one based on direct diode modulation and the second using additional electro-optic modulator (EOM) based shaping, are investigated, with up to 0.5mJ (25kHz) and 1.0mJ (12.5kHz) pulse energies achieved, respectively, for 100ns pulses with user-defined pulse shapes. Our results indicate that further energy scaling with shaped output pulses is primarily limited by the maximum pulse peak power available from the seed laser diode and the dynamic range offered by the first generation of EOMs at 2µm
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
Designer pulses for precise machining of silicon -a step towards photonic compositions
No full textThe past decade has seen the introduction of high performance short-pulse systems such as fiber and disk lasers with repetition rates in the several hundred-kHz range. These have provided the user with a wide range of interaction parameters to chose from. The availability of high speed optical imaging techniques has also provided the opportunity to explore high-speed laser matter interactions in greater detail. In this paper we demonstrate a single pulse study of a decaying tail in the pulse envelope using "unfilled" and "energy filled" pulses. We demonstrate a Pulsed digital holography (PDH) system used to study the shock wave dynamics, laser induced plasma and energy deposition efficiencies of single and multipulse interactions of 200 ns shaped laser pulses, with a temporal resolution of <10 ns. Finally, we demonstrate novel designer pulses that show improved material response and increased penetration depth at a fraction of the energetic cost of conventional pulses
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