Topic
Transformation optics
About: Transformation optics is a research topic. Over the lifetime, 2687 publications have been published within this topic receiving 102378 citations.
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TL;DR: The proposed transformation tackles the difficulty caused by the fact that the lowest multipole in three-dimensional electromagnetic radiation is dipole rather than monopole, which plays an important role in determining the cloaking modes: ideal cloaking, sensor cloaking and resonance.
Abstract: The ideal transformation optics cloaking is accompanied by shielding: external observations do not provide any indication of the presence of a cloaked object, nor is any information about the fields outside detectable inside the cloaked region. In this paper, a transformation is proposed to cloak three-dimensional objects for electromagnetic waves in sensor mode, i.e., cloaking accompanied by degraded shielding. The proposed transformation tackles the difficulty caused by the fact that the lowest multipole in three-dimensional electromagnetic radiation is dipole rather than monopole. The loss of the surface impedance of the sensor plays an important role in determining the cloaking modes: ideal cloaking, sensor cloaking and resonance.
16 citations
TL;DR: In this article, the authors proposed a reflectionless design of an optical waveguide coupler that is nonmagnetic and homogeneous using the linear coordinate transformation of triangles from virtual space to physical space.
Abstract: In this paper, we propose a reflectionless design of an optical waveguide coupler that is nonmagnetic and homogeneous. The coupler is designed using the linear coordinate transformation of triangles from virtual space to physical space. The common problem of reflections from the boundaries of a nonmagnetic coupler is remedied by analytically specifying the common vertex of triangles in such a way that the Jacobian matrix determinant becomes equal for all transformed triangles. The device performs ideal transmission without distorting the beam profile. We employ the effective medium theory to demonstrate the realizability of the device by using consecutive dielectric layers. We present a procedure to specify the dielectric constants of the layers from common existing optical materials. Numerical finite-element simulations confirm the functionality and the reflectionless property of the proposed designs.
16 citations
TL;DR: It is shown that the proposed model offers a feasible route to fabricating 3D optical NIMs by 'bottom-up' approach through adjusting structural parameters, and only the dimensions of the unit cells satisfy the effective medium theory.
Abstract: As a consequent work of the two-dimensional (2D) dendritic metamaterial which has been systematically studied in our previous work, a model of three-dimensional (3D) sphere-rod shaped structure is presented. Based on Drude model of the dielectric function of silver in the visible region, the parametric curves of electromagnetic response to the incident fields have been retrieved from detailed simulations. It is shown that the simultaneously negative values of permittivity and permeability in the optical range lead to a negative refractive index (NIM) through adjusting structural parameters, only the dimensions of the unit cells satisfy the effective medium theory. We therefore conclude that the proposed model offers a feasible route to fabricating 3D optical NIMs by ‘bottom-up’ approach.
16 citations
TL;DR: In this paper, the tunneling phenomenon occurring in a pair structure made of epsilon-negative (ENG) and mu-negative metamaterials is experimentally studied.
Abstract: In this paper, the tunneling phenomenon occurring in a pair structure made of epsilon-negative (ENG) and mu-negative (MNG) metamaterials is experimentally studied. The ENG and MNG metamaterials are fabricated using coplanar waveguide loading with lumped-element series capacitors and shunt inductors. The properties of the tunneling mode are investigated by means of the transfer-matrix method, based on the experiment parameters of effective permittivity and permeability. The results show that the tunneling frequency is independent of the pair length and the electric field is highly localized at the interface of the ENG-MNG pair. These features illustrate that the pair behaves as a cavity with strongly enhanced electric field and with dimensions beyond the half-wavelength limit.
16 citations
TL;DR: In this paper, a generalised confocal lenslet array is proposed to realize transformation-optical devices from structures of micro-structured sheets called generalized confocal lenseslet arrays.
Abstract: We describe a way to realise transformation-optical devices from structures of micro-structured sheets called generalised confocal lenslet arrays. The resulting devices should work for all visible light, and they should be relatively easy and cheap to (mass-)produce on the scale of metres, but they suffer from field-of-view limitations and significant transmission loss. Furthermore, the mapping between electromagnetic space and physical space is not through stigmatic imaging, but integral imaging. As an example application of this technology, we design and simulate an architectural window that cloaks insulation material with the aim of reducing heat loss.
16 citations