1,721,034 research outputs found
Dataset for Microengineering of Optical Properties of GeO2 Glass by Ultrafast Laser Nanostructuring
No full textData for the paper F. Zhang, A. Cerkauskaite, R. Drevinskas, P. G. Kazansky, J. Qiu, Advanced Optical Materials 2017, 1700342. </span
Square-shape distribution of ZnO crystals in glass by using a spatial light modulator
No full textWe report on square-shape distribution of ZnO crystals in glass by simultaneous femtosecond laser irradiation at multiple spots with the application of a spatial light modulator. Raman spectra and Raman mapping were used to characterize the formation of ZnO crystals and distribution of ZnO crystals, respectively. The shapes of the laser-modified region and the distribution of ZnO crystals were compared between the cases of one spot irradiation and multiple spot irradiation. The elemental distributions of the laser-modified region were investigated by an Electron Probe Microanalyzer
Self-organized periodic crystallization in unconventional glass created by an ultrafast laser for optical attenuation in the broadband near-infrared region
No full textThe construction of functional photonic structures in transparent solids for various applications, such as 3D displays, optical information processing, and tunable lasers, is of great scientific and technological importance. Here, self-assembled crystallite-based grating nanostructures are created in an unconventional multicomponent glass with an ultrafast laser. The novel nanogratings are organized as periodically assembled crystalline and amorphous phases, exhibiting strong polarization?dependent birefringence. The Ta2O5 component in the glass strongly contributes to the creation of nanogratings. Furthermore, a picosecond laser rather than a femtosecond laser is established to more suitably create nanogratings in the target glass, proving the critical role of thermal accumulation during nanoscale crystallization. Finally, nanogratings are demonstrated to be broadband variable near-infrared optical attenuators with a high attenuation ratio, indicating the potential application of nanogratings in optical information processing at communication wavelengths. These findings provide new directions for fabricating nanogratings in functional glasses for advanced integrated photonics and offer information for revealing the mechanism of nanograting formation. Novel self-organized nanograting structures with periodically assembled crystalline and amorphous phases are created in La2O3–Ta2O5–Nb2O5 glass by an ultrafast laser. Heat accumulation and the Ta2O5 content strongly contribute to the nanograting formation. The fabricated nanograting arrays exhibit a broadband polarization-dependent attenuation effect in the near-infrared region, which indicates the potential uses in the optical information processing at communication wavelengths
Ultrafast Laser Inducing Continuous Periodic Crystallization in the Glass Activated via Laser‐Prepared Crystallite‐Seeds
No full textTailoring ultrafast light–matter interaction as an enabler to create functional periodic crystalline patterns inside transparent dielectrics is of great scientific and technological significance but remains a tremendous challenge because of plenty of unclarified process details and physical mechanisms. Here, a dynamic process of ultrafast laser‐induced continuous periodic crystallization (CPC) to generate self‐organized crystal arrays (CAs) inside the glass is reported. The crystallite‐seeds induced by ultrafast laser are revealed to offer an auxiliary effect that can initiate and maintain the CPC process, which promises the high‐efficiency writing of CAs. The auxiliary effect originates from photo‐induced defects in the crystallite‐seeds, functions by drastically decreasing the pulse energy threshold for writing CAs, and can be manipulated by tuning the glass compositions and laser parameters. The created CAs are erasable and rewritable, which allows for potential applications in optical information encryption and data storage. This work not only opens up an avenue for creating embedded periodic crystalline patterns with extremely high efficiency but also helps to clarify the dynamics of ultrafast laser nanostructuring inside transparent dielectrics
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Confocal Raman imaging of femtosecond laser induced microstructures in germanate glasses
No full textLocalized microstructures were induced in a germanate glass by irradiation with a focused 800 nm, 250 kHz femtosecond laser pulses. Compared with unirradiated glass, an increase in intensity and a frequency shift of the Raman scattering bands have been observed in a ring-shaped region inside the laser-modified structure. After annealing the sample near the glass transition temperature, the ring-shaped contrast due to enhanced Raman scattering faded away. We propose that the increase in Raman scattering band intensity may be due to local compression of the glass induced by the femtosecond laser pulses irradiation
- …
