Hybrid confinement of optical and mechanical modes in a bullseye optomechanical resonator

Optomechanical cavities have proven to be an exceptional tool to explore fundamental and technological aspects of the interaction between mechanical and optical waves. Such interactions strongly benefit from cavities with large optomechanical coupling, high mechanical and optical quality factors, and mechanical frequencies larger than the optical mode linewidth, the so called resolved sideband limit. Here we demonstrate a novel optomechanical cavity based on a disk with a radial mechanical bandgap. This design confines light and mechanical waves through distinct physical mechanisms which allows for independent control of the mechanical and optical properties. Our device design is not limited by unique material properties and could be easily adapted to allow large optomechanical coupling and high mechanical quality factors with other promising materials. Finally, our demonstration is based on devices fabricated on a commercial silicon photonics facility, demonstrating that our approach can be easily scalable.Comment: 16 pages, 11 figure

As interfaces entre moda e literatura em O Coronel Chabert de Honoré de Balzac

The legacy left by great literature authors finds dialog with writers who regard fashion nowadays as a complex and wide universe, leaving behind the idea of fashion as a simple elite’s frivolous expression, and considering it a powerful instrument of sociological analysis. Honoré de Balzac, in the 19th century, had already noticed the profound connection between fashion and literature. Thereafter, in the first decades of the 20th century, the Bakhtin Circle would provide significant contributions to the understanding of both domains as cultural products, thus, necessarily marked by ideology. Also, the publications of the French philosopher and scholar of hypermodernity, Gilles Lipovetsky, help to investigate several fashion references in the 1844 version of Le Colonel Chabert. This paper attempts to show how fashion constitutes a relevant element to build the diegesis, the characters’ perception about themselves and about others, and, in an intra- and extratextual movement, the view of the post-Revolution French society. Finally, this paper seeks to combine domains not very often linked and to present the opportunity of an enlargement of perspectives on the literary text and its social environment.O legado deixado por grandes autores da literatura estabelece diálogos na atualidade com escritores que pensam a moda sob uma perspectiva mais abrangente, de forma a vê-la não mais como mera expressão frívola de elites, mas como um poderoso instrumento de análise sociológica. Honoré de Balzac, no século XIX, já havia percebido a profunda ligação entre moda e literatura. Nas primeiras décadas do século XX, o Círculo de Bakhtin viria a elaborar contribuições significativas para o entendimento de ambas as áreas como produtos culturais e, portanto, ideológicos. Igualmente, os trabalhos do filósofo e estudioso dos fenômenos da hipermodernidade, Gilles Lipovetsky, ajudarão em uma investigação e reflexão sobre as acepções de moda contidas no romance O Coronel Chabert, publicado por Balzac na versão final em 1844. Verificar-se-á de que maneira a moda constitui um elemento substancial para a construção da diegese, da visão dos personagens sobre si, sobre os outros e, em um movimento intra e extratextual, da sociedade como um todo. Este trabalho intenta, portanto, valer-se de uma convergência de áreas tão próximas, mas pouco aproximadas de fato, para tecer relações do texto literário com o meio social do qual provém, destacando o papel da moda nessa dinâmica

Third-harmonic generation in silica wedge resonators

Whispering-gallery-mode microcavities are known to have high optical quality factor, making them suitable for nonlinear optical interactions. Here, third-harmonic generation is observed using a relatively small radius wedge silicon oxide optical microcavity. The small radii wedge microdisks can be dispersion-tailored to obtain either normal or anomalous group velocity dispersion. In our case, we operate in the normal dispersion regime preventing frequency comb generation by suppressing infrared cascading four-wave mixing. This allows for a clean third harmonic generation at phase-matched visible optical modes. Tunability of the third-harmonic emission is obtained due to a combination of the thermo-optical and Kerr effects. An additional thermal control of the phase matching condition allows for optimizing third-harmonic generation, and agreement between this process and couple-mode theory is demonstrated.Comment: 6 pages, 6 figure

Efficient anchor loss suppression in coupled near-field optomechanical resonators

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQElastic dissipation through radiation towards the substrate is a major loss channel in micro-and nanomechanical resonators. Engineering the coupling of these resonators with optical cavities further complicates and constrains the design of low-loss optomechanical devices. In this work we rely on the coherent cancellation of mechanical radiation to demonstrate material and surface absorption limited silicon near-field optomechanical resonators oscillating at tens of MHz. The effectiveness of our dissipation suppression scheme is investigated at room and cryogenic temperatures. While at room temperature we can reach a maximum quality factor of 7.61k (fQ-product of the order of 10(11) Hz), at 22 K the quality factor increases to 37k, resulting in a fQ-product of 2 x 10(12) Hz.25253134731361FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ2008/57857-22012/17610-32012/17765-7153044/2013-

Magnetic response dependence of ZnO based thin films on Ag doping and processing architecture

Multifunctional and multiresponsive thin films are playing an increasing role in modern technology. This work reports a study on the magnetic properties of ZnO and Ag-doped ZnO semiconducting films prepared with a zigzag-like columnar architecture and their correlation with the processing conditions. The films were grown through Glancing Angle Deposition (GLAD) co-sputtering technique to improve the induced ferromagnetism at room temperature. Structural and morphological characterizations have been performed and correlated with the paramagnetic resonance measurements, which demonstrate the existence of vacancies in both as-cast and annealed films. The magnetic measurements reveal changes in the magnetic order of both ZnO and Ag-doped ZnO films with increasing temperature, showing an evolution from a paramagnetic (at low temperature) to a diamagnetic behavior (at room temperature). Further, the room temperature magnetic properties indicate a ferromagnetic order even for the un-doped ZnO film. The results open new perspectives for the development of multifunctional ZnO semiconductors, the GLAD co-sputtering technique enables the control of the magnetic response, even in the un-doped semiconductor materials.The Brazilian agencies CNPq, CAPES partially supports the research. From Portugal side, this work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2020 and the junior research contract (A.F.). Financial support from the Basque Government Industry Department under the ELKARTEK. HAZITEK and PIBA programs is also acknowledged

Coleta de recursos e atividade externa de abelhas campeiras de Scaptotrigona sp. e Plebeia aff. flavocincta (Hymenoptera, Apidae, Meliponini) no Semiárido da Caatinga.

Este trabalho avaliou a qualidade de recursos e a atividade externa de abelhas campeiras de Scaptotrigona sp. e Plebeia aff. flavocincta na Caatinga

Public awareness and engagement in relation to the coastal oil spill in northeast Brazil

Social media data is a rich source of information to assess human activities in catastrophic events. Here, we use social media data to understand how the 2019 Brazilian oil spill influenced social attitudes. Data were collected from the globally popular Instagram platform between August 1, 2019 and March 1, 2020. First, we manually identified the 5 most popular (portuguese language) hashtags related to the oil spill #oleonononordeste;#desastreambiental;#ma rsemoleo;#sosnordeste;#ma rsempetroleo. In the sequence, we collected information on captions, post metadata and users associated with posts retrieved using the selected hashtags. We identified a total of 7,413 posts. These posts were grouped in topics: government (47.76%), protest (24.37%), volunteers (24.45%), biodiversity (0.003%), origin (0.006%), tourism (0.008%) and others (0.016%). All topics had the peak of posts in October and November 2019. Nevertheless, interest in the oil spill was temporary, with most posts appearing in the 2-4 months after the beginning of the disaster. Our findings illustrate the enormous potential of using social media data for understanding and monitoring human engagement with environmental disasters, but also suggest that conservationists and environmental groups may only have a limited 'window of opportunity' to engage and mobilize public support for remediation and restoration efforts.Peer reviewe