Near-Field Enhancement Through a Single Subwavelength Aperture with Gaps Inside

Abstract

Structured subwavelength apertures have been studied widely to enhance the transmission or obtain super resolution, such as bull's eye hole, H-shaped aperture, and bowtie aperture. In this letter, we present another structured aperture with two gaps inside, which can also lead to nearfield enhancement. And the resonance wavelength can be tuned by the geometric parameters of the gaps. The enhancement of this gap-aperture depends strongly on the polarization of the incident wave. Only the polarization perpendicular to the connecting line of the two gaps can realize the enhancement. We attribute the near-field enhancement of this structured aperture to the resonance excitation of the localized surface plasmon. We combine the tooth-aperture and our gap-aperture together and this special aperture can achieve stronger enhancement and super resolution simultaneously.

Coupling between plasmonic nanohole array and nanorod array: the emerging of a new extraordinary optical transmission mode and epsilon-near-zero property

“…the NH array combing with other nanostructures, have attracted wide interest. Structures such as hole-particle [7,8], hole-disk [8][9][10], rod on hole [11], rod in hole [8,[12][13][14] and split hole structures [14][15][16][17], have been proposed and investigated for the application of quantitative multispectral biosensing, optical trapping and imaging, nonlinear optics, solar energy conversion [12], etc. These compound NH structures offer more parametric design freedom, and new optical phenomena could be realized.…”

Novel SNOM Probes Based on Nanofocusing in Asymmetric Structures

“…Such methods have been extensively used to investigate novel aperture shapes using, for example, the finite difference time domain method (FDTD) or the field susceptibility technique and in most of the cases considering apertures in thin metal films [21,24,[26][27][28]. Furthermore, the analysis of wave propagation in tapered structures (either traditional conical tapers or structures modified with corrugations or multiple tapers) with an aperture at the end has been carried out using the finite difference beam propagation method [65], the FDTD method [18,19], the body of revolution FDTD method (BOR-FDTD) [48], the multiple multipole method (MMP) [66].…”

“…Another route followed for the improvement of the performance of aperture probes has been the implementation of other aperture shapes different from the typical circular design: rectangular, square, slit, elliptical, C-shaped, I-shaped or dumbbell, H-shaped, bowtie, connected and separated double aperture, triangular, rod hole and tooth hole, gap apertures have been analysed and/or fabricated in fiber-and cantilever-based probes [20][21][22][23][24][25][26][27][28]. The improved throughput and field localization for some preferential input polarizations is due to the strong asymmetry of such aperture shapes and to the excitation of SPPs.…”

The effect of nanorod position on the plasmonic properties of the complex nanorod in nanohole arrays

“…Among the various metasurface structures studied, the complex subwavelength nanohole (NH) arrays, i.e. NHs combined with other nanostructure arrays, such as hole-particle [1][2][3], hole-disk [2][3][4], rod on hole [5], rod in hole [2,[6][7][8][9] and split hole structures [8,[10][11][12], have recently become the focus of research due to their peculiar extraordinary optical transmission (EOT) properties.…”