Lens or resonator? Electromagnetic behavior of an extended hemielliptic lens for a sub-millimeter-wave receiver

The behavior of a 2D model of an extended hemielliptic silicon lens of a size typical for THz applications is accurately studied for the case of a plane E-wave illumination. The full-wave analysis of the scattering problem is based on the Mutter's boundary integral-equations (MB1E) that are uniquely solvable. A Calerkin discretization scheme with a trigonometric basis leads tu a very efficient numerical algorithm. The numerical results related to the focusability of the lens versus its rear-side extension and the angle of the plane-wave incidence, as well as near-field profiles, demonstrate strong resonances. Such effects can change the principles of optimal design of lens-based receivers. © 2004 Wiley Periodicals, Inc

Resonance lens antenna analysis for MM-wave applications

We report what is to our knowledge the first accurate theoretical investigation of the electromagnetic behavior of 2-D elliptical lenses of finite wavelength-scale size. The role of internal resonances in the focal domain formation is studied. A proposal of a narrow-band receiver based on a hemielliptic lens tuned to a resonance is discussed. Possible features of such a lens-coupled receiver are stability of the resonance field with respect to the angle of arrival of incident wave and several times greater values of the peak field intensity that may potentially lead to higher sensitivity and better scanning performance. In the analysis, we use the Muller boundary integral equation (BIE) technique. This full-wave mathematically rigorous method is combined with trigonometric Galerkin discretization to result in the efficient numerical solution for an arbitrary set of the electrical, geometrical, and material parameters. Numerical results are generated for a quartz elliptical lens (ε= 3.8) with dimensions typical to mm-wave radar applications. Near field analysis, lens-focusing properties and lens frequency-dependent performance are presented

Photonic molecules and spectral engineering

This chapter reviews the fundamental optical properties and applications of pho-tonic molecules (PMs) - photonic structures formed by electromagnetic coupling of two or more optical microcavities (photonic atoms). Controllable interaction between light and matter in photonic atoms can be further modified and en-hanced by the manipulation of their mutual coupling. Mechanical and optical tunability of PMs not only adds new functionalities to microcavity-based optical components but also paves the way for their use as testbeds for the exploration of novel physical regimes in atomic physics and quantum optics. Theoretical studies carried on for over a decade yielded novel PM designs that make possible lowering thresholds of semiconductor microlasers, producing directional light emission, achieving optically-induced transparency, and enhancing sensitivity of microcavity-based bio-, stress- and rotation-sensors. Recent advances in material science and nano-fabrication techniques make possible the realization of optimally-tuned PMs for cavity quantum electrodynamic experiments, classical and quantum information processing, and sensing.Comment: A review book chapter: 29 pages, 19 figure

Ab initio calculations of optical properties of silver clusters: cross-over from molecular to nanoscale behavior

Electronic and optical properties of silver clusters were calculated using two different \textit{ab initio} approaches: 1) based on all-electron full-potential linearized-augmented plane-wave method and 2) local basis function pseudopotential approach. Agreement is found between the two methods for small and intermediate sized clusters for which the former method is limited due to its all-electron formulation. The latter, due to non-periodic boundary conditions, is the more natural approach to simulate small clusters. The effect of cluster size is then explored using the local basis function approach. We find that as the cluster size increases, the electronic structure undergoes a transition from molecular behavior to nanoparticle behavior at a cluster size of 140 atoms (diameter $\sim 1.7$\,nm). Above this cluster size the step-like electronic structure, evident as several features in the imaginary part of the polarizability of all clusters smaller than Ag$_\mathrm{147}$, gives way to a dominant plasmon peak localized at wavelengths 350\,nm$\le\lambda\le$ 600\,nm. It is, thus, at this length-scale that the conduction electrons' collective oscillations that are responsible for plasmonic resonances begin to dominate the opto-electronic properties of silver nanoclusters

Exact near fields of 2-D models of extended hemielliptic lenses made of rexolite, quartz and silicon

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Optimization of small size lenses for radar applications

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Validation of FDTD-2D for high-Q resonances description

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Test of the FDTD accuracy in the analysis of the scattering resonances associated with high-Q whispering-gallery modes of a circular cylinder

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Small hemielliptic dielectric lens antenna analysis: boundary integral equations vs. GO and PO

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