In this letter, we investigate the image field of the quasi-monochromatic random source in the two-dimensional negative-index slab. The prominent temporal-coherence gain of the image is observed in the numerical simulations even when the frequency-filtering effects are very weak. We find that the signals originating from the source will take the different time-"group" retarded time to reach the image location along the different optical paths. Based on the new physical picture, a simple phenomenological theory is constructed to obtain the image field and demonstrate that the temporal-coherence gain is from different "group" retarded time. The phenomenological theory agrees well with the FDTD simulation and the strict Green's function method. These results should have important impacts on the study of coherence mechanism and the design of novel devices.
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http://dx.doi.org/10.1364/oe.14.012295 | DOI Listing |
Nanophotonics
March 2022
State Key Lab of Optical Technologies on Nano-fabrication and Micro-engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China.
Phys Rev Lett
October 2021
Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106, USA.
The optical response of crystals is most commonly attributed to electric dipole interactions between light and matter. Although metamaterials support "artificial" magnetic resonances supported by mesoscale structuring, there are no naturally occurring materials known to exhibit a nonzero optical-frequency magnetic polarizability. Here, we experimentally demonstrate and quantify a naturally occurring nonzero magnetic polarizability in a layered semiconductor system: two-dimensional (Ruddlesden-Popper phase) hybrid organic-inorganic perovskites.
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August 2017
Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia.
All-angle negative refraction (AANR) of phononic crystals and its frequency range are dependent on mechanical properties of constituent materials and their spatial distribution. So far, it is impossible to achieve the maximum operation frequency range of AANR theoretically. In this paper, we will present a numerical approach for designing a two-dimensional phononic crystal with broadband AANR without negative index.
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January 2016
Advanced Technology Institute, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
Eliminating curved refracting lensing components used in conventional projection, imaging and sensing optical assemblies, is critical to enable compactness and miniaturisation of optical devices. A suitable means is replacing refracting lenses with two-dimensional optical media in flat-slab form, to achieve an equivalent optical result. One approach, which has been the focus of intense research, uses a Veselago lens which features a negative-index metamaterial.
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April 2013
Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA.
We report the experimental demonstration of a broadband negative refractive index obtained in a labyrinthine acoustic metamaterial structure. Two different approaches were employed to prove the metamaterial negative index nature: one-dimensional extractions of effective parameters from reflection and transmission measurements and two-dimensional prism-based measurements that convincingly show the transmission angle corresponding to negative refraction. The transmission angles observed in the latter case also agree very well with the refractive index obtained in the one-dimensional measurements and numerical simulations.
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