Improved optical enhancement using double-width plasmonic gratings with nanogaps

Darweesh, Ahmad A.; Bauman, Stephen J.; Herzog, Joseph B.

doi:10.1364/prj.4.000173

Cited by 21 publications

(14 citation statements)

References 87 publications

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“…Metamaterial gradient index diffraction gratings, composed of metallic and dielectric parts, are utilized in gradient index optics applications [11], in multiband electromagnetic absorbers [12], and in the improvement of near-field optical enhancement [13]. Recently, all-dielectric gradient metamaterials have received particular attention and have been shown to assist significantly in subdiffraction confinement and guiding of light without metals [14], in achieving very high transmission efficiency [15,16], in electromagnetic mode conversion [17], and in controllable coloring [18].…”

Section: Introductionmentioning

confidence: 99%

Anomalous reflection of visible light by all-dielectric gradient metasurfaces

Tsitsas

Valagiannopoulos

2017

J. Opt. Soc. Am. B

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Plane wave scattering by a planar metasurface composed of two periodically alternating rectangular dielectric rods is considered. A rigorous integral equation methodology is employed for the analysis and the accurate determination of the reflected and transmitted fields. Systematic optimizations with respect to the configuration's parameters are performed, which reveal that it is possible to obtain significantly enhanced anomalous reflection (with simultaneously suppressed ordinary reflection predicted by Snell's law) with power varying from 92% to almost 100% of the input one, depending on the color of the incident light. It is shown that these reflection properties are supported by metasurfaces easily realizable with specific low-loss dielectric materials. In this way, several all-dielectric optimal designs are reported that can be used in numerous applications demanding anomalous reflection in the visible range.

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Section: Introductionmentioning

confidence: 99%

Anomalous reflection of visible light by all-dielectric gradient metasurfaces

Tsitsas

Valagiannopoulos

2017

J. Opt. Soc. Am. B

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“…4(d), can be more beneficial than that of standard single-width structures for photodetector and spectroscopy enhancement applications. 75,76 These works help to demonstrate the value of nanomasking fabrication, which allows for the dual-width grating structure with the added benefit of nanoslit separation.…”

Section: Nanomasking Fabricationmentioning

confidence: 99%

Fabrication and analysis of metallic nanoslit structures: advancements in the nanomasking method

Bauman

Darweesh

Debu

et al. 2018

J. Micro/Nanolith. MEMS MOEMS

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, "Fabrication and analysis of metallic nanoslit structures: advancements in the nanomasking method," J. Micro/Nanolith. MEMS MOEMS 17(1), 013501 (2018), doi: 10.1117/1.JMM.17.1.013501. Abstract. This work advances the fabrication capabilities of a two-step lithography technique known as nanomasking for patterning metallic nanoslit (nanogap) structures with sub-10-nm resolution, below the limit of the lithography tools used during the process. Control over structure and slit geometry is a key component of the reported method, exhibiting the control of lithographic methods while adding the potential for mass-production scale patterning speed during the secondary step of the process. The unique process allows for fabrication of interesting geometric combinations such as dual-width gratings that are otherwise difficult to create with the nanoscale resolution required for applications, such as nanoscale optics (plasmonics) and electronics. The method is advanced by introducing a bimetallic fabrication design concept and by demonstrating blanket nanomasking. Here, the need for the secondary lithography step is eliminated improving the mass-production capabilities of the technique. Analysis of the gap width and edge roughness is reported, with the average slit width measured at 7.4 AE 2.2 nm. It was found that while no long-range correlation exists between the roughness of either gap edge, and there are ranges in the order of tens of nanometers over which the slit edge roughness is correlated or anticorrelated across the gap. This work helps quantify the nanomasking process, which aids in future fabrications and leads toward the development of more accurate computational models for the optical and electrical properties of fabricated devices. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 UnportedLicense. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…Efficiently designed gradient metasurfaces can control the propagation direction of an incident wave over subwavelength distances, modify the optical wavefront, bend and focus light, generate anomalous reflection and refraction phenomena as well as prescribed distributions of electromagnetic waves [5][6][7][8][9]. Besides, metamaterial gradient index diffraction gratings, composed of metallic and dielectric parts, may assist in gradient index optics applications [10], in multiband electromagnetic absorbers [11], and in the improvement of the near-field optical enhancement [12]. More recently, it has been elaborated that dielectric materials with low-loss electromagnetic responses, realized by using completely transparent and high-refractive-index dielectric building blocks, may offer the possibility of subdiffraction confinement and guiding of light without metals [13].…”

Section: Introductionmentioning

confidence: 99%

Efficient integral equation modeling of scattering by a gradient dielectric metasurface

Tsitsas

2017

EPJ Applied Metamaterials

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-Plane-wave scattering by a gradient dielectric metasurface, composed of a dielectric slab on which has been etched an infinitely periodic grating, is analyzed by means of rigorous semi-analytical integral equation techniques based on the Method of Moments with entire domain basis functions. The electric field integral equation is considered with unknown function the electric field on the grating and is then solved by applying an entire domain Galerkin's technique. The proposed methodology is characterized by high numerical stability and controllable accuracy; the obtained solution is analytic with the sole approximation of the final truncation of the expansion functions sets. The operation of the metasurface as a narrow-band reflection frequency filter is investigated. Moreover, it is also shown that under certain conditions anomalous reflection and transmission can be generated even for a metasurface composed of conventional materials. The numerical results obtained provide design guidelines, which may pave the way for more systematic investigations of gradient dielectric metasurfaces assisting the control and manipulation of electromagnetic waves.

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Improved optical enhancement using double-width plasmonic gratings with nanogaps

Cited by 21 publications

References 87 publications

Anomalous reflection of visible light by all-dielectric gradient metasurfaces

Anomalous reflection of visible light by all-dielectric gradient metasurfaces

Fabrication and analysis of metallic nanoslit structures: advancements in the nanomasking method

Efficient integral equation modeling of scattering by a gradient dielectric metasurface

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