Metalenses at visible wavelengths: Diffraction-limited focusing and subwavelength resolution imaging

Khorasaninejad, Mohammadreza; Chen, Wei Ting; Devlin, Robert C.; Oh, Jaewon; Zhu, Alexander Y.; Capasso, Federico

doi:10.1126/science.aaf6644

Cited by 2,795 publications

(2,051 citation statements)

References 37 publications

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“…For example, a metalens that consists of TiO 2 nanofins on a glass substrate has been designed and fabricated, with a NA = 0.8 and an efficiency as high as 86% in the visible range [66]. In this case, the required phase is conferred by rotation of the nanofin according to the geometric Pancharatnam-Berry phase, showing that they are able to provide diffraction-limited focal spots at arbitrary design wavelengths.…”

Section: Dielectric Nanoresonatorsmentioning

confidence: 99%

Recent Progress in Far-Field Optical Metalenses

Naserpour¹,

Hashemi²,

Rodríguez³

2017

Metamaterials - Devices and Applications

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In this chapter, a review of the recent advances in optical metalenses is presented, with special emphasis in their experimental implementation. First, the Huygens' principle applied to ultrathin engineered metamaterials is introduced for the purpose of giving curvature to the wavefront of free-space wave fields. Primary designs based on metallic nanoslits and holey screens occasionally with variant width are first examined. Holographic plasmonic lenses are also explored offering a promising route to realize nanophotonic components. More recent metasurfaces based on nano-antenna resonators, either plasmonic or high-index dielectric, are analyzed in detail. Furthermore, 2D material lenses in the scale of a few nanometers enabling the thinnest lenses to date are here considered. Finally, dynamically reconfigurable focusing devices are reported for creating a scenario with new functionalities.

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Section: Dielectric Nanoresonatorsmentioning

confidence: 99%

Recent Progress in Far-Field Optical Metalenses

Naserpour¹,

Hashemi²,

Rodríguez³

2017

Metamaterials - Devices and Applications

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“…Luckily, even if it is well known that interaction of the magnetic field part of the light with matter is much weaker than the electric field one 24 , lately, plasmonic-like resonances have been shown also in dielectrics. Indeed, nanoparticles made of high-refractive-index semiconductors (such as germanium, tellurium, GaAs, AlGaAs, GaP, and silicon), do not suffer from large intrinsic absorption at the visible, infrared, and telecom frequencies, thereby strongly attracting the attention and emerging as a promising alternative to plasmonic nanostructures for nanophotonic applications 25,26 .…”

Section: Introductionmentioning

confidence: 99%

Linear ultrafast dynamics of plasmon and magnetic resonances in nanoparticles

et al. 2017

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In this study we present an analytical description of the ultrafast localized surface plasmon and magnetic resonance dynamics in a single nanoparticle (Ag or Si, respectively), driven by an ultrashort (fs-timescale) Gaussian pulse. Three possible scenarios have been found depending on the incident field, i.e. pulse duration much shorter, similar and much longer than the localized surface plasmon resonance (LPSR) lifetime. A rich physics arises for τ pulse < τLSP R, even in the linear regime. The surface plasmon dynamics is manifested as (i) a temporal delay of the surface plasmon excitation with regard to the freely propagating pulse and (ii) as a negative exponential tail after the exciting pulse is over. In addition, for sub-fs pulses clear oscillations in the near-field decay have been observed. A similar scenario has been observed considering a non-absorbing Si sphere. Nanoparticle resonance dynamics may lead to a wealth of new phenomena and applications in nanophotonics such as multipole order resonances interference, pulse induced delay or temporal shaping on the fsscale, high harmonic generation, attosecond near-field pulse sources and electron acceleration from metasurface or 3D engineered nanostructures.

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“…9 With careful design these resonators can support electric and magnetic dipole resonances simultaneously and render a 2π phase coverage for the transmitting light. This provides the ability to control the phase and amplitude of the light locally thus enabling wavefront engineering.…”

Section: Introductionmentioning

confidence: 99%

All-dielectric metasurface for wavefront control at terahertz frequencies

Dharmavarapu

Bhattacharya

et al. 2018

Nanophotonics Australasia 2017

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Recently, metasurfaces have gained popularity due to their ability to offer a spatially varying phase response, low intrinsic losses and high transmittance. Here, we demonstrate numerically and experimentally a silicon metasurface at THz frequencies that converts a Gaussian beam into a Vortex beam independent of the polarization of the incident beam. The metasurface consists of an array of sub-wavelength silicon cross resonators made of a high refractive index material on substrates such as sapphire and CaF 2 that are transparent at IR-THz spectral range. With these substrates, it is possible to create phase elements for a specific spectral range including at the molecular finger printing around 10 µm as well as at longer THz wavelengths where secondary molecular structures can be revealed. This device offers high transmittance and a phase coverage of 0 to 2π. The transmittance phase is tuned by varying the dimensions of the meta-atoms. To demonstrate wavefront engineering, we used a discretized spiraling phase profile to convert the incident Gaussian beam to vortex beam. To realize this, we divided the metasurface surface into eight angular sectors and chose eight different dimensions for the crosses providing successive phase shifts spaced by π/4 radians for each of these sectors. Photolithography and reactive ion etching (RIE) were used to fabricate these silicon crosses as the dimensions of these cylinders range up to few hundreds of micrometers. Large 1-cm-diameter optical elements were successfully fabricated and characterised by optical profilometry.

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Metalenses at visible wavelengths: Diffraction-limited focusing and subwavelength resolution imaging

Cited by 2,795 publications

References 37 publications

Recent Progress in Far-Field Optical Metalenses

Recent Progress in Far-Field Optical Metalenses

Linear ultrafast dynamics of plasmon and magnetic resonances in nanoparticles

All-dielectric metasurface for wavefront control at terahertz frequencies

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