Lattice Induced Transparency in Metasurfaces

Lattice modes are intrinsic to the periodic structures and their occurrence can be easily tuned and controlled by changing the lattice constant of the structural array. Previous studies have revealed excitation of sharp absorption resonances due to lattice mode coupling with the plasmonic resonances. Here, we report the first experimental observation of a lattice induced transparency (LIT) by coupling the first order lattice mode (FOLM) to the structural resonance of a metamaterial resonator at terahertz frequencies. The observed sharp transparency is a result of the destructive interference between the bright mode and the FOLM mediated dark mode. As the FOLM is swept across the metamaterial resonance, the transparency band undergoes large change in its bandwidth and resonance position. Besides controlling the transparency behaviour, LIT also shows a huge enhancement in the Q-factor and record high group delay of 28 ps, which could be pivotal in ultrasensitive sensing and slow light device applications.Comment: 5 figure

Electronic Change in University Libraries: role of Tehnologies in J&K

Conversion is essential activity for library’s, as library is a growing organism and hence to manage it, is a vital and tedious task. In this paper I want to suggest a mechanism to change management which can focus that change management was relevant not only in the initial phase, but also in the developing phase of the library’s spiral cycle and is a continuous process. The ultimate goal of this work is to promote a better understanding of the process of Change Management in libraries. Research paper describes the management of technological change with in the staff of libraries of Jammu & Kashmir State Universities. It describes how much placate staff is with the technology, digitization and how much they resist change and reasons for their resistance including their perceptions for uncertainty. It also describes librarians’ role and strategies adopted by them to manage technological change and digitization. It further describes the role of communication in managing technological change and digitization. Exchange of ideas, thoughts, opinions, etc. can be regarded as an effective tool in digitized environment to lead staff and change proficiently and successfully. In the knowledge society change is the only constant thing and it is inevitable. Information Communication Technologies have brought sea changes in the field of information sharing, retrieval and dissemination.Â

Multiple Triple-Point Fermions in Heusler Compounds

Using the density functional theoretical calculations, we report a new set of topological semimetals X$_{2}$YZ (X = \{Cu, Rh, Pd, Ag, Au, Hg\}, Y = \{Li, Na, Sc, Zn, Y, Zr, Hf, La, Pr, Pm, Sm, Tb, Dy, Ho, Tm\} and Z =\{Mg, Al, Zn, Ga, Y, Ag, Cd, In, Sn, Ta, Sm\}), which show the existence of multiple topological triple point fermions along four independent $C_{3}$ axes. These fermionic quasiparticles have no analogues elementary particle in the standard model. The angle-resolved photoemission spectroscopy is simulated to obtain the exotic topological surface states and the characteristic Fermi arcs. The inclusion of spin-orbit coupling splits the triple-point into two Dirac points. The triple-point fermions are exhibited on the easily cleavable (111) surface and are well separated from the surface $\bar{\Gamma}$ point, allowing them to be resolved in the surface spectroscopic techniques. This intermediate linearly dispersive degeneracy between Weyl and Dirac points may offer prospective candidates for quantum transport applications

Coupling between a dark and a bright eigenmode in a terahertz metamaterial

Terahertz time domain spectroscopy and rigorous simulations are used to probe the coupling between a dark and a bright plasmonic eigenmode in a metamaterial with broken symmetry. The metamaterial consists of two closely spaced split ring resonators that have their gaps in non-identical positions within the ring. For normal incidence and a fixed polarization both lowest order eigenmodes of the split ring resonators can be excited; although one of them has to be regarded as dark since coupling is prohibited because of symmetry constraints. Emphasis in this work is put on a systematic evaluation of the coupling effects depending on a spectral tuning of both resonances