Terahertz field enhancement by a metallic nano slit operating beyond the skin-depth limit

Seo, Myung Hwan; Park, H. R.; Koo, Sukmo; Park, D. J.; Kang, Ju Hyung; Suwal, O. K.; Choi, Seong Soo; Planken, Paul C. M.; Park, G. S.; Park, N. K.; Park, Q. H.; Kim, D. S.

doi:10.1038/nphoton.2009.22

Cited by 508 publications

(370 citation statements)

References 39 publications

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“…Therefore, this marks an important attribute of coatings with negative permittivities, as such profile lowering in antenna technology at selected resonances offers dramatic improvements in miniaturized and even nanoscale antenna designs, which could not otherwise be feasible [14]. This strong radiation resonance for nearly zero coating thickness can be regarded as being related to nanofocusing [21][22][23][24], in which strong field localization is achieved in the nanoscale, offering numerous modern applications such as imaging, spectroscopy, and optical ultra-microscopy, all with nanometer-scale spatial resolution, allowing even for single-molecule detection. It is also observed from Fig.…”

Section: Materials and Thickness Variationsmentioning

confidence: 99%

“…As such, E 0 will also have to be zero, according to (21), so as to achieve a non-infinite c n (a "zero divided by zero" situation). Hence, regardless trivial or nontrivial solutions of (22), E 0 has to vanish. Under such conditions, we arrive at the classical eigenvalue problem entailing the matrix equation: [Z][C] = [0], for which non-trivial solutions exist only when |Z| = 0, which is the characteristic equation, as defined by (22).…”

Section: Resonant and Non-resonant Conditionsmentioning

confidence: 99%

“…Hence, regardless trivial or nontrivial solutions of (22), E 0 has to vanish. Under such conditions, we arrive at the classical eigenvalue problem entailing the matrix equation: [Z][C] = [0], for which non-trivial solutions exist only when |Z| = 0, which is the characteristic equation, as defined by (22). This means that non-vanishing field solutions exist (nontrivial eigenvector [C]) even without the presence of an excitation source (E 0 = 0), as of classical eigen-mode theory.…”

Section: Resonant and Non-resonant Conditionsmentioning

confidence: 99%

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Spherical Slotted Antenna Coated With Double Layer of Materials Having Combinations of Singly and Doubly Negative Parameters and Consequences of Mode Resonances

Ng¹

2012

PIER B

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Abstract-This work studies the influence of material coatings, especially combined natural and metamaterials, on the radiation properties of a practical dipole like antenna, represented by a slotted conducting sphere. The selected geometry allows an exact solution to the problem, and thus the development of exact expressions for the antenna parameters, like the radiated power and directivity. It is shown that for materials with combined positive and negative parameters, mode resonances can occur at thinner coatings, the thickness of which can be made diminishingly small by proper selection of coating parameters. In particular, at these resonances the antenna directivity, while being finite, becomes independent of the antenna size and coating parameters.

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Section: Materials and Thickness Variationsmentioning

confidence: 99%

Section: Resonant and Non-resonant Conditionsmentioning

confidence: 99%

Section: Resonant and Non-resonant Conditionsmentioning

confidence: 99%

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Spherical Slotted Antenna Coated With Double Layer of Materials Having Combinations of Singly and Doubly Negative Parameters and Consequences of Mode Resonances

Ng¹

2012

PIER B

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“…[23][24][25][26][27][28] On the other hand, a single infinitely long narrow slit was shown to lead to a significant field enhancement inside the slit leading to broadband EOT. 29,30 A slit etched in a thin metal film can be depicted as a nanocapacitor charged by the light-induced charges on the surrounding metal surface. 29 The charge concentration increases as the gap width (a) decreases and the wavelength (k) increases, leading to extreme FE at the nanoscale.…”

mentioning

confidence: 99%

“…29,30 A slit etched in a thin metal film can be depicted as a nanocapacitor charged by the light-induced charges on the surrounding metal surface. 29 The charge concentration increases as the gap width (a) decreases and the wavelength (k) increases, leading to extreme FE at the nanoscale. [29][30][31] This gives nanoslits great potential at (long) terahertz wavelengths (e.g., see reports on FE ¼ 720 at 0.1 THz in 70 nm-wide single slits 29 and FE ¼ 760 at 0.2 THz in 40 nm-wide slits arrays 30 ).…”

mentioning

confidence: 99%

Skirting terahertz waves in a photo-excited nanoslit structure

Shalaby

Fabiańska

Peccianti

et al. 2014

Applied Physics Letters

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Terahertz fields can be dramatically enhanced as they propagate through nanometer-sized slits. The enhancement is mediated by a significant accumulation of the induced surface charges on the surrounding metal. This enhancement is shown here to be dynamically modulated while the nanoslits are gradually shunted using a copropagating optical beam. The terahertz fields are found to skirt the nanoscale photo-excited region underneath the slits, scattering to the far field and rigorously mapping the near field.

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Ultrasensitive Terahertz Nano‐Probing for Semiconductors Using Nanogap Structures

Bahk

Seo

2021

Digital Encyclopedia of Applied Physics

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There has been a growing interest in exploring novel opto‐electrical behaviors and response of carriers under nonequilibrium conditions in semiconductor nanoscale materials for applications of photocurrent and operation of photodetectors. Terahertz waves have shown substantial promise for these applications, with the merit of direct observation of transient carrier dynamics and conductivity changes in semiconductor materials. Especially, to investigate surface carrier dynamics of such nanoscale semiconductor materials under photoexcitation, one can use nanosized materials such as nanofilms, nanowires, and nanoparticles, which have a very large surface‐to‐volume ratio. In this article, we introduce ultrafast phenomena in semiconductors investigated by terahertz probes. In particular, recent studies on how to observe carrier dynamics in a semiconductor with a spatial resolution of nanoscale levels below the diffraction limit of terahertz wave, using well‐tailored metallic nanogap structures are mainly introduced. Metallic nanostructures having the ability to confine electromagnetic waves in a volume much smaller than wavelength play an important role in many application areas such as subwavelength waveguides, metamaterials, biochemical sensing, and photovoltaic technology. Strong local electromagnetic field confinement and enhancement accompanied by metallic nanostructures including nanogaps and nanotips have been widely used to manipulate interaction between electromagnetic waves and target materials. In addition to their diverse applications, their fundamental importance has received a great deal of attention in nano‐optics and nano‐photonics. The tunability of resonances by the geometrical effect of metal nanostructures can be exploited to increase the interaction efficiency between the nanostructures and electromagnetic waves at specific wavelength regions of interest.

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Terahertz field enhancement by a metallic nano slit operating beyond the skin-depth limit

Cited by 508 publications

References 39 publications

Spherical Slotted Antenna Coated With Double Layer of Materials Having Combinations of Singly and Doubly Negative Parameters and Consequences of Mode Resonances

Spherical Slotted Antenna Coated With Double Layer of Materials Having Combinations of Singly and Doubly Negative Parameters and Consequences of Mode Resonances

Skirting terahertz waves in a photo-excited nanoslit structure

Ultrasensitive Terahertz Nano‐Probing for Semiconductors Using Nanogap Structures

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