Multipole methods for nanoantennas design: applications to Yagi-Uda configurations

International audienceWe present a detailed formalism allowing analytical calculations of the radiative properties of nanoantennas. This formalism does not rely on dipole approximations and utilizes multipolar multiple-scattering theory. The improvement in both accuracy and calculation speeds offered by this formulation provides significant advantages that are used in this work to study Yagi-Uda-type nanoantennas. We provide a study that questions the necessity of the reflector particle in nanoantennas

Hubungan Beban Kerja Dengan Kejadian Hipertensi Pada Tenaga Pengajar Di SMA N 1 Amurang Kabupaten Minahasa Selatan

Salah satu faktor yang mempengaruhi terjadinya peningkatan tekanan darah adalah beban kerja yang dilakukan seseorang yang melebihi batas waktu normal. Suatu jenis pekerjaan yang dilakukan melebihi batas waktu kerja memicu terjadinya kelelahan kerja sehingga mempengaruhi aspek beban mental, fisik, dan waktu kerja. Hasil penelitian dari Riskesdas (2013) terhadap hipertensi menurut karakteristiknya didapat bahwa status pekerjaan juga dapat mempengaruhi terjadinya hipertensi dengan prevalensi sebesar 24,72%. Tujuan penelitian ini untuk mengetahui hubungan beban kerja dengan kejadian hipertensi di SMA N 1 Amurang Kabupaten Minahasa Selatan. Desain Penelitian yang digunakan bersifat observasional analitik yaitu cross sectional. Teknik pengambilan sampel dilakukan dengan accidental sampling dengan jumlah sampel 33 orang. Hasil penelitian menggunakan uji statistik chi square didapatkan nilai p = 0.023 < α = 0.05. Kesimpulan hasil penelitian menunjukkan adanya hubungan beban kerja dengan kejadian hipertensi pada tenaga pengajar di SMA N 1 Amurang Kabupaten Minahasa Selatan. Saran dapat ditambahkan sebagai informasi dibidang keperawatan medikal bedah untuk dijadikan acuan penelitian selanjutnya bahwa beban kerja yang berat memicu terjadinya hipertensi

Ultracompact and unidirectional metallic antennas

International audienceWe investigate the angular redistribution of light radiated by a single emitter located in the vicinity of dipolar silver nanoparticles. We point out the fundamental role of the phase differences introduced by the optical path difference between the emitter and the particle and demonstrate that the polarizability of the metallic nanoparticle alone cannot predict the emission directionality. In particular, we show that collective or reflective properties of single nanoparticles can be controlled by tuning the distance of a single emitter at a λ/30 scale. These results enable us to design unidirectional and ultracompact nanoantennas composed of just two coupled nanoparticles separated by a distance achievable with biological linkers

Silicon Mie Resonators for Highly Directional Light Emission from monolayer MoS2

Controlling light emission from quantum emitters has important applications ranging from solid-state lighting and displays to nanoscale single-photon sources. Optical antennas have emerged as promising tools to achieve such control right at the location of the emitter, without the need for bulky, external optics. Semiconductor nanoantennas are particularly practical for this purpose because simple geometries, such as wires and spheres, support multiple, degenerate optical resonances. Here, we start by modifying Mie scattering theory developed for plane wave illumination to describe scattering of dipole emission. We then use this theory and experiments to demonstrate several pathways to achieve control over the directionality, polarization state, and spectral emission that rely on a coherent coupling of an emitting dipole to optical resonances of a Si nanowire. A forward-to-backward ratio of 20 was demonstrated for the electric dipole emission at 680 nm from a monolayer MoS2 by optically coupling it to a Si nanowire

Signatures of exciton coupling in paired nanoemitters

An exciton formed by the delocalized electronic excitation of paired nanoemitters is interpreted in terms of the electromagnetic emission of the pair and their mutual coupling with a photodetector. A formulation directly tailored for fluorescence detection is identified, giving results which are strongly dependent on geometry and selection rules. Signature symmetric and antisymmetric combinations are analyzed and their distinctive features identified

Correlates of licensure examination and college academic performance of Teacher Education graduates

This study examines the performance of Bachelor of Secondary Education (BSED) graduates from one of the Cordillera Administrative Region\u27s State Colleges and Universities from 2016 to 2018. It evaluated academic performance across three domains: general education, professional education, specialization, and overall LET performance. The relationship between academic performance and LET performance was also investigated. In this study, the descriptive-correlational research method was used. The collected data was statistically treated with frequency, mean, and percentage on descriptive, ANOVA on testing significant difference with LSD post hoc analysis, and Pearson r correlation on test of performance relationship. The findings revealed that the academic performance of BSED graduates was strong across the board. On the LET, the graduates had a higher percentage of passers than non-passers. The majority of examinees passed all components of the LET, but struggled in the specialization subjects. Academic performance is strongly linked to LET performance. Therefore, the Bachelor of Secondary education (BSE) curriculum and instruction of the college is relevant in preparing the students for the teaching profession. The Bachelor of Secondary education (BSE) curriculum contents is relevant in passing the Licensure Examination for Teachers (LET). More so that it needs an emphasis on the field of specialization. And, graduates\u27 academic standing has a great impact on their performance on the Licensure Examination for Teachers (LET). Thus, the Teacher Education Department must maintain and improve academic performance by reviewing syllabi and ensuring that Teaching-Learning Activities (TLA\u27s) and Assessment Tasks (AT\u27s) are implemented, particularly in the major field. With a need to focus more on strengthening LET examinees\u27 performance across specialization subjects, Teacher Education may consider developing an improved instructional plan and prioritizing strategies that will address issues in students\u27 academic performance. As a foundation for the Department\u27s policy directions and interventions, additional research on other variables influencing teaching-learning performance may be conducted

Small dielectric spheres with high Refractive index as new multifunctional elements for optical devices

The future of ultra-fast optical communication systems is inevitably connected with progress in optical circuits and nanoantennas. One of the key points of this progress is the creation of elementary components of optical devices with scattering diagrams tailored for redirecting the incident light in a desired manner. Here we demonstrate theoretically and experimentally that a small, simple, spatially homogeneous dielectric subwavelength sphere with a high refractive index and low losses (as some semiconductors in the visible or near infrared region) exhibits properties allowing to utilize it as a new multifunctional element for the mentioned devices. This can be achieved by taking advantage of the coherent effects between dipolar and multipolar modes, which produce anomalous scattering effects. The effects open a new way to control the directionality of the scattered light. The directional tuning can be obtained in a practical way just by a change in the frequency of the incident wave, and/or by a well-chosen diameter of the sphere. Dielectric nanoparticles with the required optical properties in the VIS-NIR may be now readily fabricated. These particles could be an efficient alternative to the widely discussed scattering units with a more complicated design.This research was partly supported by MICINN (Spanish Ministry of Science and Innovation) through project FIS2013-45854-P and by the Ministry of Education and Science of Russian Federation through grant 14.Z50.31.0034