Subwavelength focusing behavior of high numerical-aperture phase Fresnel zone plates under various polarization states

Mote, Rakesh G.; Yu, Siu Fung; Zhou, Wei; Li, Xiao Feng

doi:10.1063/1.3263728

Cited by 43 publications

(30 citation statements)

References 14 publications

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“…The experimentally measured elliptic focal spot was equal to FWHM = 0.63λ on the minor semi-axis. In the FDTD-aided simulation [4], obtaining a focal spot of size FWHM = 0.39λ was reported. Focusing a linearly polarized wave with an amplitude ZP of 0.5-µm focus has also been numerically simulated using Richards-Wolf formulae [4].…”

Section: Introductionmentioning

confidence: 99%

“…In the FDTD-aided simulation [4], obtaining a focal spot of size FWHM = 0.39λ was reported. Focusing a linearly polarized wave with an amplitude ZP of 0.5-µm focus has also been numerically simulated using Richards-Wolf formulae [4]. Superfocusing with a plasmonic microzone plate fabricated in a silver film applied on a glass substrate has been studied [5].…”

Section: Introductionmentioning

confidence: 99%

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Tight focusing of laser light using a chromium Fresnel zone plate

et al. 2017

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Using near-field scanning microscopy, we demonstrate that a 15-µm zone plate fabricated in a 70-nm chromium film sputtered on a glass substrate and having a focal length and outermost zone's width equal to the incident wavelength λ = 532 nm, focuses a circularly polarized Gaussian beam into a circular subwavelength focal spot whose diameter at the fullwidth of half-maximum intensity is FWHM=0.47λ. This value is in near-accurate agreement with the FDTD-aided numerical estimate of FWHM=0.46λ. When focusing a Gaussian beam linearly polarized along the y-axis, an elliptic subwavelength focal spot is experimentally found to measure FWHMx=0.42λ (estimated value FWHMx=0.40λ) and FWHMy=0.64λ. The subwavelength focal spots presented here are the tightest among all attained so far for homogeneously polarized beams by use of non-immersion amplitude zone plates.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tight focusing of laser light using a chromium Fresnel zone plate

et al. 2017

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“…Angular spectrum analysis in the Fourier domain demonstrates that the silver zone plate provides more evanescent waves than does a glass zone plate [10]. The symmetry of focus spot under different polarization statuses was further reported [11,12]. However, there is no reason to believe that the Fresnel zone plate (FZP) structure is already optimized for subwavelength focusing with high numerical aperture (NA>0.9).…”

Section: Introductionmentioning

confidence: 91%

Subwavelength Focusing Using Plasmonic Wavelength-Launched Zone Plate Lenses

Wang

Zhou

et al. 2011

Plasmonics

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We propose a plasmonic wavelength-launched Fresnel zone plate structure for subwavelength focusing. The plasmonic structure consists of a central circular groove surrounded by 12 transparent and opaque zones. All the zones with widths smaller than one half of the incident wavelength are used to enhance the field of evanescent waves in the transmission. Based on the finite-difference time-domain analysis, a focus spot with a full-width at half-maximum of 270 nm (= 0.4λ in ) can be achieved, accompanied by a largely reduced depolarization effect. The sharp waistline indicates that the surface waves are largely converged in the region of focus.

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“…Later [39] the ability of subwavelength focusing of high numerical aperture FZP was also shown in optical waveband.…”

Section: Resolution Of Fzpa With Sub-wavelength Focal Distancementioning

confidence: 98%

Reference Phase in Diffractive Lens Antennas: A Review

Minin

2011

J Infrared Milli Terahz Waves

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We review a free parameter in the design of Fresnel zone plate lens antennas. Historically, zone plate antennas have been designed with a specific choice for this parameter, which can be taken as a type of phase reference. Two methods of interpreting the parameter have been identified, either in terms of a reference radius or equivalently a reference phase. Here, for simplicity, we treat this variable parameter as a reference phase. Importantly, the reference phase can be chosen to have non-standard values which have been shown to improve important aspects of antenna performance and to add a new functionality to zone plate antennas.

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Subwavelength focusing behavior of high numerical-aperture phase Fresnel zone plates under various polarization states

Cited by 43 publications

References 14 publications

Tight focusing of laser light using a chromium Fresnel zone plate

Tight focusing of laser light using a chromium Fresnel zone plate

Subwavelength Focusing Using Plasmonic Wavelength-Launched Zone Plate Lenses

Reference Phase in Diffractive Lens Antennas: A Review

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