Role of epsilon-near-zero substrates in the optical response of plasmonic antennas

Kim, Jong Bum; Dutta, Aveek; Naik, Gururaj V.; Giles, Alexander J.; Bezares, Francisco J.; Ellis, Chase T.; Tischler, Joseph G.; Mahmoud, Ahmed M.; Çağlayan, Hümeyra; Glembocki, O. J.; Kildishev, Alexander V.; Caldwell, Joshua D.; Boltasseva, Alexandra; Engheta, Nader

doi:10.1364/optica.3.000339

Cited by 182 publications

(125 citation statements)

References 52 publications

Supporting

Mentioning

119

Contrasting

Order By: Relevance

“…We note that when the ENZ medium is sufficiently thick, the antenna resonance gets locked to the zero permittivity wavelength of the ENZ material [37]. Nevertheless a metasurface that incorporates a thick ENZ material will also exhibit enhanced nonlinear response because a dynamic change in the substrate's refractive index necessarily modifies the resonance wavelength of the antenna.…”

mentioning

confidence: 90%

“…Thus, ENZ material with lower intrinsic damping could increase the saturation threshold. The nonlinear response could be further enhanced by maximizing the overlap between the near-field of the antennas and the ITO layer, by choosing antennas (dielectric or metallic) with higher quality factors, and by choosing an ENZ material with lower intrinsic damping [18,36] .We note that when the ENZ medium is sufficiently thick, the antenna resonance gets locked to the zero permittivity wavelength of the ENZ material [37]. Nevertheless a metasurface that incorporates a thick ENZ material will also exhibit enhanced nonlinear response because a dynamic change in the substrate's refractive index necessarily modifies the resonance wavelength of the antenna.…”

mentioning

confidence: 97%

See 1 more Smart Citation

Large optical nonlinearity of nanoantennas coupled to an epsilon-near-zero material

et al. 2018

View full text Add to dashboard Cite

The size and operating energy of a nonlinear optical device are fundamentally constrained by the weakness of the nonlinear optical response of common materials. Here, we report that a 50-nm-thick optical metasurface made of optical dipole antennas coupled to an epsilon-near-zero material exhibits a broadband (∼ 400 nm bandwidth) and ultrafast (recovery time less than 1 ps) intensitydependent refractive index n 2 as large as −3.73 ± 0.56 cm 2 /GW. Furthermore, the metasurface exhibits a maximum optically induced refractive index change of ±2.5 over a spectral range of ∼ 200 nm. The inclusion of low-Q nanoantennas on an epsilon-near-zero thin film not only allows one to design a metasurface with an unprecedentedly large nonlinear optical response but also offers the flexibility to tailor the sign of the response. Our technique allows one to overcome a longstanding challenge in nonlinear optics, namely that of finding a material for which the nonlinear contribution to the refractive index is of the order of unity. It consequently offers the possibility of designing low-power nonlinear nano-optical devices with orders-of-magnitude smaller footprints.All-optical signal processing and computation are often hailed as breakthrough technologies for the next generation of computation and communication devices. Two important parameters of such devices, energy consumption and size, critically depend on 1 the strength of the nonlinear optical response of the materials from which they are made. However, materials typically exhibit an extremely weak nonlinear optical response. This property makes designing subwavelength all-optical active devices extremely difficult. Thus, all-optical active devices tend to have large footprints, which limits the integration density to many orders of magnitude smaller than what can be achieved in a state-of-the-art electronic integrated circuits [1,2]. Thus, materials with much stronger nonlinear optical responses are needed in order to enable integrated high-density on-chip nonlinear optical devices.Over the years several approaches have been explored to enhance the intrinsic nonlinear optical response of materials, including local field enhancement using composite structures [3,4,5], plasmonic structures [6,7], and metamaterials [8,9,10,11]. However, these techniques offer only limited control over the magnitude (and sign when applicable) of the wavelength-dependent nonlinear response, and typically involve a trade-off between the strength of the nonlinearity and the spectral position of the peak nonlinear response. It has been reported recently that materials with vanishingly small permittivitycommonly known as epsilon-near-zero or ENZ material -exhibit intriguing linear [12,13,14,15,16] and large nonlinear responses [17,18,19,20,21]. However, an ENZ material has a large nonlinear response over only a relatively narrow spectral range. Furthermore, the zero-permittivity wavelength, strength of the nonlinear response, and the losses depend on the optical properties of the ENZ material. In com...

show abstract

mentioning

confidence: 90%

mentioning

confidence: 97%

Large optical nonlinearity of nanoantennas coupled to an epsilon-near-zero material

et al. 2018

View full text Add to dashboard Cite

show abstract

“…When the area of the single‐zero ZIM approaches zero, the results would be the same as those obtained for doped DZIM. We note that single‐zero ZIM like ENZ media have the advantage of easy fabrication in the optical regime by using conductive materials with Drude or Drude‐like dispersions, such as doped semiconductors, indium tin oxide, aluminum‐doped zinc oxide, etc.…”

Section: Versatile Mechanisms For Absorption Controlmentioning

confidence: 99%

“…In this work, by utilizing the unique constraint of constant fields within zero‐index medium (ZIM, with permittivity or/and permeability near zero), we propose to realize CPA via the photonic doping of ZIM with absorptive defects. The concept and theory of “photonic doping” of an epsilon‐near‐zero (ENZ) medium, i.e.…”

Section: Introductionmentioning

confidence: 99%

Coherent Perfect Absorption via Photonic Doping of Zero‐Index Media

Luo

Liu

Hang

et al. 2018

Laser & Photonics Reviews

View full text Add to dashboard Cite

Coherent perfect absorption, as time‐reversed lasing, is achieved via appropriate interference of waves in absorbers and provides attractive opportunities for flexible control of light scattering and absorption. Here, the authors theoretically and experimentally demonstrate the realization of coherent perfect absorption by using photonic doping of zero‐index media with absorptive defects. Interestingly, the coherent perfect absorption is independent of the size and shape of this “doped” zero‐index medium absorber, as well as the position of the doping defects. This exceptional absorption property can be well explained via the photonic doping theory for zero‐index media. Moreover, the authors demonstrate that the doping scheme also enables novel ways to control absorption, such as multiple channels and multiple doping defects, etc. This work proposes a unique doping approach for advanced coherent perfect absorption with versatile control functionalities.

show abstract

“…[1][2][3][4] In recent years, optical antennas have attracted considerable interest and hold promise to improve the performance in a large number of applications, such as near-field scanning optical microscopy, 5 photo-detectors, 6 photovoltaic cells, 7 thermal emitters, 8 saturable absorbers, 9 upconverted incoherent nonlinear emission, 10,11 single-molecule fluorescence enhancement, 12 and third harmonic generation (THG) enhancement. 13 Due to the lightning-rod effect and the coupling of two metal nanotriangles (coupled plasmons), it has been shown that bowtie nanoantennas 14 can achieve stronger intensity enhancement than other comparable structures such as rod-, ellipse-, disk-, and cross-shaped nanoantennas.…”

mentioning

confidence: 99%

Investigating the origin of third harmonic generation from diabolo optical antennas

Shi

Andrade

Kim

et al. 2017

Applied Physics Letters

View full text Add to dashboard Cite

We propose to use diabolo nanoantennas for experimentally investigating the origin of the enhanced third harmonic generation by localized surface plasmon polaritons. In such a geometry, the opposing apexes of bowties are electrically connected by a thin gold nanorod, which has two important functions in discriminating the point of harmonic generation. First, the inserted gold nanorod shifts the field enhancement area to be far away from the dielectric substrate material. Next, the accumulation of free charges at the adjacent bowtie tips produces a strong electric field inside the gold nanorod. The diabolo nanoantennas allow us to examine the contribution of the bare gold susceptibility to the third harmonic conversion. Our results reveal that the bare gold does not significantly enhance the harmonic generation at high pump intensity. From this, we deduce that in regular bowtie antennas, the enhanced harmonic photons mainly arise from the substrate sapphire that is located in the feedgap of the bowtie, where the electric near-field is significantly enhanced by the localized surface plasmons. Published by AIP Publishing. https://doi

show abstract

Role of epsilon-near-zero substrates in the optical response of plasmonic antennas

Cited by 182 publications

References 52 publications

Large optical nonlinearity of nanoantennas coupled to an epsilon-near-zero material

Large optical nonlinearity of nanoantennas coupled to an epsilon-near-zero material

Coherent Perfect Absorption via Photonic Doping of Zero‐Index Media

Investigating the origin of third harmonic generation from diabolo optical antennas

Contact Info

Product

Resources

About