In this paper, we will propose that magnetic-resonance nanostructures in a metal surface could be used to realize extraordinary optical transmission (EOT). Toward this goal, we designed and fabricated a one dimensional diatomic chain of slit-hole resonator (SHR). Due to the strong exchange current interaction, a type of magnetic plasmon (MP) propagation mode with a broad frequency bandwidth was established in this system. Apparent EOT peaks induced by the MP mode were observed in our measured spectra at infrared frequencies. The strongest EOT peak was obtained at 1.07 eV with an incident angle of 20 degree. The measured dependence of EOT peaks on the incident angle coincided with the theoretical results quite well. This proposed MP propagation mode in SHR structure has good potential applications in multifrequency nonlinear optical processes.
We revisit the problem of extraordinary transmission of acoustic (electromagnetic) waves through a slit in a rigid (perfectly conducting) wall. We use matched asymptotic expansions to study the pertinent limit where the slit width is small compared to the wall thickness, the latter being commensurate with the wavelength. Our analysis focuses on near-resonance frequencies, furnishing elementary formulae for the field enhancement, transmission efficiency, and deviations of the resonances from the Fabry-Perot frequencies of the slit. We find that the apertures' near fields play a dominant role, i…
In this paper we describe a way to achieve the extraordinary transmission regime from sub-wavelength slits carved on semiconductor substrates. Unlike metals, the dielectric permittivity of typical semiconductors like GaAs or GaP is negative beginning in the extreme UV range (lambda <= 270nm). We show that the metal-like response of bulk semiconductors exhibits surface plasmon waves that lead to extraordinary transmission in the UV and soft X-ray ranges. The importance of realistic material response versus perfect conductors is also discussed. These findings may be important in high resolution …
The extraordinary transmission of light through a nano slit in a metal film is enhanced by introducing a nano cavity antenna formed by a nearby metallic nano-strip over the slit opening. For a fixed wavelength, the width of the metallic nano-strip should be chosen to make the horizontal metal-insulator-metal waveguide of finite length resonant as a Fabry-Perot cavity. When such a cavity antenna is used to enhance the transmission through a non-resonant nano slit, the slit should be opened at a position with maximal magnetic field in the horizontal resonant cavity. It is shown that an optimized…
We show that, a metasurface composed of subwavelength metallic slit array embedded in an asymmetric environment can exhibit either extraordinary optical transmission (EOT) or extraordinary optical diffraction (EOD). By employing an analytical model expansion method and the diffraction order chart in k-vector space, we found that the resonance decaying pathway of the local slit cavity mode can be tuned to either 0th or -1st diffraction order by changing the parallel wavevector, which gives rise to enhanced 0th transmission (EOT) of the structure for small incident angles, and enhanced -1st diff…
Continuous films of metals like gold and silver with a thickness of a few tens of nm have poor optical transmission in the visible and infrared. However, the same films become largely transparent when the transmission is mediated by coupled surface plasmon polaritons on the two surfaces of the film. Likewise, it is expected that optical transmission through a hole in an opaque metal film would be negligible if the size of the hole is much smaller than the wavelength of the incident radiation. Contrary to this, it was found a few years ago that opaque metal films perforated with a periodic arra…
This paper has presented inversely determining the resonant configuration of the bilateral nanostructures for periodic metallic slits with extraordinary optical transmission performance. The topology optimization approach is utilized to implement the inverse design procedure. Several geometrical configurations of the bilateral nanostructures are derived for periodic metallic slits. The resonant performance of the derived nanostructures are demonstrated by the transmission spectra, where the transmission peak is presented at the specified wavelength in the inverse design procedure. This provide…
We study the problem of resonant extraordinary transmission of electromagnetic and acoustic waves through subwavelength slits in an infinite plate, whose thickness is close to a half-multiple of the wavelength. We build on the matched-asymptotics analysis of Holley & Schnitzer (Wave Motion, 91 102381, 2019), who considered a single-slit configuration assuming an idealised formulation where dissipation is neglected and the electromagnetic and acoustic problems are analogous. We here extend that theory to include thin dissipative boundary layers associated with finite conductivity of the plate i…
The photoelectron momentum shifts along the laser propagation are investigated by the time-dependent perturbation theory for diatomic molecules, such as H$_2^+$, N$_2$ and O$_2$. Such longitudinal momentum shifts characterize the photon momentum sharing in atoms and molecules, and oscillate with respect to photon energies, presenting the double-slit interference structure. The atomic and molecular contributions are disentangled analytically, which gives intuitive picture how the double-slit interference structure is formed. Calculation results show the longitudinal photoelectron momentum distr…
In this letter we present an analytical theory of Extraordinary optical transmission (EOT) through semi-transparent screens, such as thin metallic plates or high permittivity dielectric slabs. Using this theory we show that EOT appears not only for screens perforated by holes or slits, but also for screens loaded by any defects, including opaque defects. These results widen the scope of EOT concept, opening up the way to the study of new physical effects.
The incumbent technology for bringing light to the nanoscale, the near-field scanning optical microscope, has notoriously small throughput efficiencies - of the order of 10^(-4) - 10^(-5), or less. We report on a broadband, topological, unidirectionally-guiding structure, not requiring adiabatic tapering and in principle enabling near-perfect (ideally, ~100%) optical transmission through an unstructured single (POTUS) arbitrarily-subdiffraction slit at its end. Specifically, for a slit width of just lambda_eff / 72 (lambda_0 / 138) the attained normalized transmission coefficient reaches a val…
Coordinate transformation is applied to design an all-dielectric device for Extraordinary Transmission (ET) in a single sub-wavelength slit. The proposed device has a broadband feature and can be applied from microwave to visible frequency bands. Finite-Difference Time-Domain (FDTD) simulations are used to verify the device's performance. The results show that significantly increased transmission is achieved through the sub-wavelength aperture from 4 GHz to 8 GHz when the device is applied. In contrast with previously reported systems, the frequency sensitivity of the new device is very low.
Inter-slit interactions across one-dimensional arrays of sub-micro meter rectangular holes in gold films are explored. Using electron energy loss spectroscopy combined with scanning transmission electron microscopy, a series of cavity standing waves is resolved, indicating particularly high interslit interactions, about an order of magnitude larger than the intra-slit edge to edge coupling. Pronounced signal enhancements are thus induced, dominated by short-range interactions and high mode-localization, while yet, relatively long-range coherence is retained. The sub-nm electron beam, in spite …
Metallic structures with periodic array of slits are well-known to lead to extraordinary power transmission, when slits have dimensions much less than the wavelength of incident optical wave. Excellent power transmission originates from surface waves excited by incident transverse magnetic wave. Here we show that metallic structure with array of stepped-slits can transmit power of incident wave into the substrate at desired optical frequency entirely and simultaneously in terahertz frequency band by 70%, for In0.53Ga0.47As substrate. Transmitted power of the proposed structure is studied both …
Recent numerical studies have demonstrated the possibility of achieving substantial enhancements in the transmission of transverse-electric-polarized electromagnetic fields through subwavelength slits in a thin metallic screen by placing single or paired metallic cut-wire arrays at a close distance from the screen. In this Letter, we report on the first experimental evidence of such extraordinary transmission phenomena, via microwave (X/Ku-band) measurements on printed-circuit-board prototypes. Experimental results agree very well with full-wave numerical predictions, and indicate an intrinsic…
We discuss optical forces exerted on particles, either dielectric or metallic, near a subwavelength slit illuminated by a photonic nanojet. We compare those cases in which the Mie resonances are or are not excited. The configurations on study are 2D, hence those particles are infinite cylinders and, in order to obtain extraordinary transmission, the illuminating beam is p-polarized. We show the different effects of these particle resonances on the optical forces: while whispering gallery modes under those illumination conditions weaken the force strength, this latter is enhanced by localized p…
We study, and illustrate with numerical calculations, transmission enhancement by subwavelength 2D slits due to the dominant role played by the excitation of the eigenmodes of plasmonic cylinders when they are placed at the aperture entrance; and also due to reinforced and highly localized energy in the slit as a consequence of the formation of a nanojet. We show that, providing the illumination is chosen such that an aperture transmitting eigenmode is generated, the phenomenon is independent of whether or not the slit alone produces extraordinary transmission; although in the former case this…
Subwavelength-slotted parallel plate waveguides exhibit a localized electromagnetic resonance bound to the slits at a frequency slightly below the transverse electric cutoff [R. Merlin, Phys. Rev. X 2, 031015 (2012)]. The resonance is long-lived and, as opposed to the vanishingly small transmission shown by a single sub-wavelength aperture, it gives perfect transmission for perfectly-conducting plates. We show that the aperture-supported resonances of a pair of slotted copper plates have long lifetimes at THz frequencies. Finite element method calculations show that these bound resonances can …
We theoretically investigate second harmonic generation that originates from the nonlinear, magnetic Lorentz force term from single and multiple apertures carved on thick, opaque metal substrates. The linear transmission properties of apertures on metal substrates have been previously studied in the context of the extraordinary transmission of light. The transmission process is driven by a number of physical mechanisms, whose characteristics and relative importance depend on the thickness of the metallic substrate, slit size, and slit separation. In this work we show that a combination of cavi…
Periodic metallic structures are known to support resonant extraordinary transmission (EOT). When covered with graphene, these structures can be employed to effectively manipulate the light. In this work, we propose an analytical circuit model for graphene-covered one-dimensional metallic gratings. By using the circuit theory, we demonstrate that one-dimensional periodic array of cut-through slits which are covered by a continuous graphene sheet exhibit tunable EOT resonance whose amplitude, unlike its spectral position, can be dynamically tuned by varying the Fermi level of graphene. In this …
We present a concrete picture of spoof surface plasmons (SSPs) combined with cavity resonance to clarify the basic mechanism underlying extraordinary light transmission through metal films with subwavelength slits or holes. This picture may indicate a general mechanism of metallic nanostructure optics: When light is incident on a non-planar conducting surface, the free electrons cannot move homogeneously in response to the incident electric field, i.e., their movement can be impeded at the rough parts, forming inhomogeneous charge distributions. The oscillating charges/dipoles then emit photon…
Plasmonic metasurfaces based on the extraordinary optical transmission effect (EOT) can be designed to efficiently transmit specific spectral bands from the visible to the far-infrared regimes, offering numerous applications in im-portant technological fields such as compact multispectral imaging, biological and chemical sensing, or color displays. However, due to their subwavelength nature, EOT metasurfaces are nowadays fabricated with nano- and micro-lithographic techniques, requiring many processing steps and carried out in expensive cleanroom environments. In this work, we propose and expe…
The interaction between molecules and surface plasmons in defined geometries can lead to new light mater hybrid states where light propagation is strongly influenced by molecular photon absorption. Their application range from lasing LEDs to controlling chemical reactions and are relevant in light harvesting. The coupling between the electromagnetic field and molecular excitations may also lead to macroscopic extended coherent states characterized by an increase in temporal and spatial coherency. In this respect, it is intriguing to explore the coherency of the hybrid system for molecules that…
