Dual-band, double-negative, polarization-independent metamaterial for the visible spectrum

We present the first dual-band negative index metamaterial that operates in the visible spectrum. The optimized four-functional-layer metamaterial structure exhibits the first double-negative (i.e., simultaneously negative permittivity and permeability) band in the red region of the visible spectrum with a figure of merit of 1.7 and the second double-negative band in the green region of the visible spectrum with a figure of merit of 3.2. The optical behavior of the proposed structure is independent of the polarization of the incident field. This low-loss metamaterial structure can be treated as a modified version of a fishnet metamaterial structure with an additional metal layer of different thickness in a single functional layer. The additional metal layer extends the diluted plasma frequency deep into the visible spectrum above the second order magnetic resonance of the structure, hence provides a dual band operation with simultaneously negative effective permittivity and permeability. Broadband metamaterials with multiple negative index bands may be possible with the same technique by employing higher order magnetic resonances. The structure can be fabricated with standard microfabrication techniques that have been used to fabricate fishnet metamaterial structures.Comment: 26 Pages, 6 Figures, 2 Tables, 2 Medi

Plasmonic Superlens Imaging Enhanced by Incoherent Active Convolved Illumination

We introduce a loss compensation method to increase the resolution of near-field imaging with a plasmonic superlens that relies on the convolution of a high spatial frequency passband function with the object. Implementation with incoherent light removes the need for phase information. The method is described theoretically and numerical imaging results with artificial noise are presented, which display enhanced resolution of a few tens of nanometers, or around one-fifteenth of the free space wavelength. A physical implementation of the method is designed and simulated to provide a proof-of-principle, and steps toward experimental implementation are discussed

Enhancing the resolution of hyperlens by the compensation of losses without gain media

We present a method to improve the resolution of available hyperlenses in the literature. In this method, we combine the operation of hyperlens with the recently proposed plasmon injection scheme for loss compensation in metamaterials. Image of an object, which is otherwise not resolvable by the hyperlens alone, was reconstructed up to the minimum feature size of one seventh of the free-space wavelength.Comment: 4 pages, 5 figure

Negative Refraction Gives Rise to the Klein Paradox

Electromagnetic negative refraction in metamaterials has attracted increasingly great interest, since its first experimental verification in 2001. It potentially leads to the applications superior to conventional devices including compact antennas for mobile stations, imaging beyond the diffraction limit, and high-resolution radars, not to mention the anamolous wave propagation in fundamental optics. Here, we report how metamaterials could be used to simulate the "negative refraction of spin-zero particles interacting with a strong potential barrier", which gives rise to the Klein paradox--a counterintuitive relativistic process. We address the underlying physics of analogous wave propagation behaviours in those two entirely different domains of quantum and classical.Comment: 4 journal pages, 2 figure

Demet Ş. Dinler, Workers Exictence Problem [İşçinin Varlık Problemi]

Book Revie

Workforce Efficiency Increase For The Online Sales In-Store Picking Operation

The online food retailing got more attention to itself with the global coronavirus outbreak. Online marketing growth rate reached above 40% in the lockdown months. It became more important to deliver the orders faster than opponents. This study examines one of the biggest food retails company’s in-store picking operation for workforce efficiency increase. The picker job description and daily work routines observed through observation forms. The results are validated by data extracted from the Collectify system, which is used for picking operation and has all the time stamp of picker’s action. Analyzing data and combining with the output of observation forms, the new picking model proposed for the fresh departments (meat, deli, fruit & vegetable) products. Having two weeks of trial and after realizing the results with the Collectify system data, the new model helped operating costs decrease by 7,7% in the picking operation

Plasmon Injection to Compensate and Control Losses in Negative Index Metamaterials

Metamaterials have introduced a whole new world of unusual materials with functionalities that cannot be attained in naturally occurring material systems by mimicking and controlling the natural phenomena at subwavelength scales. However, the inherent absorption losses pose fundamental challenge to the most fascinating applications of metamaterials. Based on a novel plasmon injection (PI or \Pi) scheme, we propose a coherent optical amplification technique to compensate losses in metamaterials. Although the proof of concept device here operates under normal incidence only, our proposed scheme can be generalized to arbitrary form of incident waves. The \Pi-scheme is fundamentally different than major optical amplification schemes. It does not require gain medium, interaction with phonons, or any nonlinear medium. The \Pi-scheme allows for loss-free metamaterials. It is ideally suited for mitigating losses in metamaterials operating in the visible spectrum and is scalable to other optical frequencies. These findings open the possibility of reviving the early dreams of making 'magical' metamaterials from scratch.Comment: Main text, 8 pages with 4 figures; supplemental material, 21 pages with 21 figure

Turkish-Russian adversarial collaboration in Syria, Libya, and Nagorno-Karabakh

Russia and Turkey are backing opposing warring parties in three active conflicts. How­ever, this adversarial positioning has not hindered cooperation between Moscow and Ankara. They reign in opposing sides and, in effect, stage-manage their respective theatres of wars. Through multilateral arrangements, Europe is an enabler of Tur­key's position and could leverage its support to push Ankara to cooperate more effec­tively with its Western partners. (author's abstract

Role of Technology in Accounting and E-accounting

AbstractTechnological developments changed methods for carrying out tasks within the scope of accounting activities and transactions related to accounting was started to being carried out through electronic media. Growth and development growing rapidly in information technologies day by day have brought digital revolution in economic, social and cultural fields. Our era is information era and when we acknowledge that accounting is an information system, the way and processes of transacting businesses of enterprises have changed with usage of information technologies in enterprises and this influenced accounting closely. Necessity of keeping up with changing conditions of accounting led educators and practitioners to new pursuits. Enabling inclusion of information era and technologic factors in education by benefiting from digital resources as well as theoretical information in accounting education provided in universities and generating an interactive environment to keep student wakeful and preferring educational model in which information technologies are used is necessary. In order to achieve that, students should be provided to take target-driven accounting courses and an educational order should be generated in which students can evaluate and interpret information beyond recording and make difference through information and communication technologies.One of digital applications produced on this issue is E-accounting. E-accounting is perception of enabling management of all activities more efficiently, affordably, flexibly than before through facilities of internet. All parties of the activity (employee-manager-customer-public body-business partner-supplier) are real-time users of the system and those sharing up-to-date information instantly. Accounting staffs that can apply this structure in enterprises through accounting education and establish this system in enterprises are needed. Therefore, quality of accounting education is a factor influencing success of employees of enterprises and hence enterprises directly. Re-structuring of accounting education and developing contents by considering present conditions are necessary with respect to train graduates having sufficient quality to respond needs of the era and