scholarly journals Absorption Enhancement in Hyperbolic Metamaterials by Means of Magnetic Plasma

2021 ◽  
Vol 11 (11) ◽  
pp. 4720
Author(s):  
Tatjana Gric ◽  
Edik Rafailov

The main features of surface plasmon polaritons (SPPs) that can propagate in a metamaterial–magnetic plasma structure are studied from theoretical perspectives. Both the conventional and imaginary parts of the dispersion relation of SPPs are demonstrated considering transverse magnetic (TM) polarization. We examine and discuss the influence of the external magnetic field. The results demonstrate that this factor dramatically alters the nature of SPPs. It is concluded that the positions and propagation lengths of SPPs can be engineered. Moreover, we present an approach allowing for an absorption enhancement that is a pivotal factor in antenna design. A unified insight into the practical methods aiming to attain hyperbolic dispersion by means of nanostructured and nanowire metamaterials is demonstrated.

2021 ◽  
pp. 097226292098394
Author(s):  
Kannan Perumal

The work ‘Corruption Measurements: Caught Between Conceptualizing the Phenomenon and Promoting New Governance Agenda?’ is a qualitative study based on reviewing the literature available on the subject. It starts with the introduction that explains the evolution of the idea of measuring corruption, its relevance to governance and associated theoretical issues. The topic, ‘Evolution of Corruption Measurements’ gives an overview about different corruption indices. While the topic ‘Challenges to Corruption Measurements’ briefly introduces the challenges faced by corruption measurements, the topics ‘Conceptualizing Corruption’ and ‘Methodological Issues’ give insight into the contentions faced by corruption measurements from different theoretical perspectives. Also, explained in these sections are how the corruption measurements have conceptualized corruption over the period of three decades; and how do they keep evolving their methods in order to become more relevant in policy advocacy. Issues associated with data aggregation also are explained in-depth in this work. This work demonstrates that though continuous methodological evolution and empirical research have helped corruption measurements to improve their acceptance level, the gap that exist between corruption control framework and practice will remain a challenge to address in future if corruption measurements do not genuinely account the contextual realities.


Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shulei Li ◽  
Lidan Zhou ◽  
Mingcheng Panmai ◽  
Jin Xiang ◽  
Sheng Lan

Abstract We investigate numerically and experimentally the optical properties of the transverse electric (TE) waves supported by a dielectric-metal heterostructure. They are considered as the counterparts of the surface plasmon polaritons (i.e., the transverse magnetic (TM) waves) which have been extensively studied in the last several decades. We show that TE waves with resonant wavelengths in the visible light spectrum can be excited in a dielectric-metal heterostructure when the optical thickness of the dielectric layer exceeds a critical value. We reveal that the electric and magnetic field distributions for the TE waves are spatially separated, leading to higher quality factors or narrow linewidths as compared with the TM waves. We calculate the thickness, refractive index and incidence angle dispersion relations for the TE waves supported by a dielectric-metal heterostructure. In experiments, we observe optical resonances with linewidths as narrow as ∼10 nm in the reflection or scattering spectra of the TE waves excited in a Si3N4/Ag heterostructure. Finally, we demonstrate the applications of the lowest-order TE wave excited in a Si3N4/Ag heterostructure in optical display with good chromaticity and optical sensing with high sensitivity.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michał Dudek ◽  
Rafał Kowerdziej ◽  
Alessandro Pianelli ◽  
Janusz Parka

AbstractGraphene-based hyperbolic metamaterials provide a unique scaffold for designing nanophotonic devices with active functionalities. In this work, we have theoretically demonstrated that the characteristics of a polarization-dependent tunable hyperbolic microcavity in the mid-infrared frequencies could be realized by modulating the thickness of the dielectric layers, and thus breaking periodicity in a graphene-based hyperbolic metamaterial stack. Transmission of the tunable microcavity shows a Fabry–Perot resonant mode with a Q-factor > 20, and a sixfold local enhancement of electric field intensity. It was found that by varying the gating voltage of graphene from 2 to 8 V, the device could be self-regulated with respect to both the intensity (up to 30%) and spectrum (up to 2.1 µm). In addition, the switching of the device was considered over a wide range of incident angles for both the transverse electric and transverse magnetic modes. Finally, numerical analysis indicated that a topological transition between elliptic and type II hyperbolic dispersion could be actively switched. The proposed scheme represents a remarkably versatile platform for the mid-infrared wave manipulation and may find applications in many multi-functional architectures, including ultra-sensitive filters, low-threshold lasers, and photonic chips.


Author(s):  
Nisar Ahmad Malik

: This mini review will give an insight into the need and usefulness of investigating the solubilization of poorly soluble drugs. Commonly used experimental and theoretical models are outlined to study the efficacy of the carrier or excipient for the poorly soluble drugs. Furthermore, the use of surface active agents for drug solubilization is discussed in correlation with the mathematical models suggested from time to time. A few experimental techniques are also discussed which would be very helpful in elucidating the interactions prevailing in the mixed systems of poorly soluble drugs and surface active agents.


2014 ◽  
Vol 16 (4) ◽  
pp. 277-295 ◽  
Author(s):  
Kate Holmes ◽  
Anita Greenhill ◽  
Rachel McLean

Purpose – The purpose of this study is to gain insight into craft and do-it-yourself (DIY) communities of practice (COPs) and how the use of technology provides ways for participants to connect, share and create. Gaining deeper insights into the practices of these communities may provide new opportunities to utilise within this flourishing domain. Design/methodology/approach – Qualitative methods were adopted to collect data and analysed through an interpretivist lens. Semi-structured interviews were conducted with members of craft and DIY COPs to gain a deep understanding of the broader ethnographic study. Existing theoretical perspectives surrounding COPs have been applied to further current perspectives. Findings – Findings from this study suggest that being part of a COP allows participants to connect to others, build creative enterprise and learn or enhance skills. Insights gained from this study indicate some of the detailed ways in which the application of technology redefines craft and DIY COPs. Research limitations/implications – This study provides a succinct exploration of a vast and fluid domain; if presented with more time and wider resources, the research would include further exploration of virtual COPs. Originality/value – The investigation provides a rich insight into the use of information and communication technologies (ICTs) within craft and DIY COPs. The application of theoretical perspectives from the area of Information Systems (IS) and Technology Management to this domain is regarded as an original research and furthers knowledge in these areas. Originality/value – The investigation provides a rich insight into the use of ICTs within craft and DIY COPs. The application of theoretical perspectives from the area of IS to the domain of craft and DIY culture is original research and extends existing concepts to include skills sharing as a previously unexplored domain.


2004 ◽  
Vol 1 (2) ◽  
pp. 209-223 ◽  
Author(s):  
ANAHID KASSABIAN

Through an examination of the labels Hear Music and Putumayo and their place in coffee shops and retail stores on the one hand, and of world music scholarship on the other, I argue that listening to world music in public spaces demands new theoretical perspectives. The kinds of tourism that take place in listening to world music inattentively suggest a kind of bi-location. Borrowing from quantum mechanics, I suggest that the term ‘entanglement’ might offer some insight into this bi-location and the ‘distributed tourism’ that I argue is taking place.


Ars Adriatica ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 379
Author(s):  
Blaženka Perica

The collection of texts Image and Anti-Image – Julije Knifer and the Problem of Representation is based on multi- and transdisciplinary research conducted by Croatian and international critics and theoreticians. They have investigated the contemporary sensibility for the questions of image and pictoriality by referring to a common starting point: the oeuvre of one of the most important Croatian artists – Julije Knifer. In their analysis of Knifer’s paintings since the early 1960s, which revolve around a single motif – the “meander” – which the artist has repeated and varied throughout his artistic career, the authors have followed the changing reception of his work from the supremacy of the high modernist image concept, such as postulated in Greenberg’s formalistic theory, until today, when theoretical proposals have become essentially different. In his introduction to the project, editor Krešimir Purgar has stressed the importance of new perspectives that Knifer’s work may offer if viewed in the context of new disciplines such as visual studies and image science. The 21 articles, grouped into five thematic sections, aim at clarifying and expanding the references of Knifer’s “meander” by taking diverse informative and original approaches that have this recent image theory as their starting point. In the context of Croatian scholarly output, this publication is notable for having accomplished a rare blend between monographic material and a series of interdisciplinary, scholarly-theoretical studies based on extremely varied perspectives, resulting in a valuable comparative miscellany, a contribution both to the actualisation and new positioning of Knifer’s art and to our insight into various analytic and interpretative approaches related to the present state of art theory. Such an approach assigns a special place to the image, to pictoriality and visuality. The theoretical perspectives of image science and the heterogeneous, plural strategies of research developed within the new image studies (image science, visual studies) assimilate and expand rather than replace the previously accepted methods, common in traditional theoretical approaches to the discipline of art history.


2017 ◽  

Researching cultural diversity is a central subject of social anthropology. 25 authors from institutes in Germany, Austria and Switzerland offer an insight into the subject, its contents and theoretical perspectives. The articles cover a variety of topics: the history of the discipline as well as basic theories and methods, subareas such as business or kinship anthropology, crosscutting issues such as anthropology of media, but also up-to-date specialised fields such as urban or development anthropology. The book is therefore invaluable for students and anyone interested in social anthropology who wants to open up fields of work, theoretical approaches and results of the subject.


Sign in / Sign up

Export Citation Format

Share Document