Showing papers by "Viktor A. Podolskiy published in 2009"
TL;DR: This work demonstrates an improvement in biosensing technology using a plasmonic metamaterial that is capable of supporting a guided mode in a porous nanorod layer and provides an enhanced sensitivity to refractive-index variations of the medium between the rods.
Abstract: Label-free plasmonic biosensors rely either on surface plasmon polaritons or on localized surface plasmons on continuous or nanostructured noble-metal surfaces to detect molecular-binding events. Despite undisputed advantages, including spectral tunability, strong enhancement of the local electric field and much better adaptability to modern nanobiotechnology architectures, localized plasmons demonstrate orders of magnitude lower sensitivity compared with their guided counterparts. Here, we demonstrate an improvement in biosensing technology using a plasmonic metamaterial that is capable of supporting a guided mode in a porous nanorod layer. Benefiting from a substantial overlap between the probing field and the active biological substance incorporated between the nanorods and a strong plasmon-mediated energy confinement inside the layer, this metamaterial provides an enhanced sensitivity to refractive-index variations of the medium between the rods (more than 30,000 nm per refractive-index unit). We demonstrate the feasibility of our approach using a standard streptavidin-biotin affinity model and record considerable improvement in the detection limit of small analytes compared with conventional label-free plasmonic devices.
1,615 citations
TL;DR: In this paper, the optical properties of plasmonic nanorod metamaterials in the epsilon-near-zero regime were analyzed and it was shown that the performance of these composites is strongly affected by nonlocal response of the effective permittivity tensor.
Abstract: We analyze the optical properties of plasmonic nanorod metamaterials in the epsilon-near-zero regime and show, both theoretically and experimentally, that the performance of these composites is strongly affected by nonlocal response of the effective permittivity tensor. We provide the evidence of interference between main and additional waves propagating in the room-temperature nanorod metamaterials and develop an analytical description of this phenomenon. Additional waves are present in the majority of low-loss epsilon-near-zero structures and should be explicitly considered when designing applications of epsilon-near-zero composites, as they represent a separate communication channel.
255 citations
TL;DR: The approach combines the diffraction gratings that generate the high-wave-vector-number modes and planar slabs of homogeneous anisotropic metamaterials that propagate these waves and combine them at the subwavelength focal spots to resolve their fundamental limitations.
Abstract: We present a technique capable of producing subwavelength focal spots in planar nonresonant structures not limited to the near-field of the source. The approach combines the diffraction gratings that generate the high-wave-vector-number modes and planar slabs of homogeneous anisotropic metamaterials that propagate these waves and combine them at the subwavelength focal spots. In a sense, the technique combines the benefits of Fresnel lens, near-field zone plates, hyperlens, and superlens and at the same time resolves their fundamental limitations. Several realizations of the proposed technique for visible, near-IR, and mid-IR frequencies are proposed, and their performance is analyzed theoretically and numerically. Generalizations of the developed approach for subdiffractional imaging and on-chip photonics are suggested.
76 citations
31 May 2009
TL;DR: Experimental evidence of excitation of additional wave in nanorod metamaterials in ENZ regime is presented and Analytical description of the phenomenon is developed and the effect on the optical response of the system is discussed.
Abstract: We present experimental evidence of excitation of additional wave in nanorod metamaterials in ENZ regime. Analytical description of the phenomenon is developed and the effect on the optical response of the system is discussed.
58 citations
TL;DR: In this paper, a novel class of semiconductor metamaterials that employ a strongly anisotropic dielectric function to achieve negative refraction in the mid-infrared region of the spectrum, ∼8.5-13μm, is reported.
Abstract: We report on a novel class of semiconductor metamaterials that employ a strongly anisotropic dielectric function to achieve negative refraction in the midinfrared region of the spectrum, ∼8.5–13 μm. We present two types of metamaterials, layered highly doped/undoped heterostructures and quantum well superlattices that are highly anisotropic. Contrary to other optical metamaterials these heterostructure systems are optically thick (up to 20 μm thick), planar, and require no additional fabrication steps beyond the initial growth. Using transmission and reflection measurements and modeling of the highly doped heterostructures, we demonstrate that these materials exhibit negative refraction. For the highly doped quantum well superlattices, we demonstrate anomalous reflection due to the strong anisotropy of the material but a determination of the sign of refraction is still difficult. This new class of semiconductor metamaterials has great potential for waveguiding and imaging applications in the long-wave inf...
54 citations
TL;DR: In this paper, the authors analyzed wave propagation in coupled planar waveguides, pointing specific attention to modal cross-talk and out-of-plane scattering in quasi-planar photonics.
Abstract: We analyze wave propagation in coupled planar waveguides, pointing specific attention to modal cross-talk and out-of-plane scattering in quasi-planar photonics. An algorithm capable of accurate numerical computation of wave coupling in arrays of planar structures is developed and illustrated on several examples of plasmonic and volumetric waveguides. An analytical approach to reduce or completely eliminate scattering and modal cross-talk in planar waveguides with anisotropic materials is also presented.
18 citations
31 May 2009
TL;DR: In this article, a planar focusing and imaging system capable of subwavelength focusing of radiation in the far field of the source was proposed and the Fourier-optics applications of these structures were presented.
Abstract: We propose a new class of planar focusing and imaging systems capable of subwavelength focusing of radiation in the far field of the source and present the Fourier-optics applications of these structures.
1 citations
31 May 2009
TL;DR: In this paper, generalized Ohm's Law is used to model the phenomenon of broadband asymmetric reflectance observed in semicontinuous metal-dielectric films in the proximity of the percolation threshold.
Abstract: Generalized Ohm's Law is used to model the phenomenon of broadband asymmetric reflectance recently observed in semicontinuous metal-dielectric films in the proximity of the percolation threshold. Qualitative agreement with experiment is achieved.
TL;DR: In this article, a technique for subwavelength far-field focusing of light in planar non-resonant structures is presented, which combines the diffraction gratings that generate high-wave vector waves and planar slabs of homogeneous anisotropic metamaterials that propagate these waves and combine them at the sub-wavelength focal spots.
Abstract: We present a technique for subwavelength far-field focusing of light in planar non-resonant structures. The approach
combines the diffraction gratings that generate high-wavevector waves and planar slabs of homogeneous anisotropic
metamaterials that propagate these waves and combine them at the subwavelength focal spots. The technique has all the
benefits of Fresnel lens, near-field zone plate, hyperlens, and superlens, and at the same time resolves their fundamental
limitations. Several realizations of hypergratings for visible, near-IR, and mid-IR frequencies are proposed, and their
performance is analyzed. Generalization of the developed approach for sub-diffractional imaging and on-chip photonics
is suggested.
02 Jun 2009
TL;DR: In this article, the authors proposed to use silver/gold sandwich structures to combine the advantages of silver and gold -two materials of choice for nanoplasmoics and metamaterials.
Abstract: We propose to use silver/gold sandwich structures to combine the advantages of silver and gold - two materials of choice for nanoplasmoics and metamaterials. We report on the preparation, characterization, and theoretical modeling of the proposed system.
TL;DR: In this paper, the authors demonstrated stimulated emission in a microring cavity formed by dye-doped polymer deposited on a gold wire, and the mode structure suggests that the stimulated emission originates from surface plasmon polaritons propagating at the gold-polymer interface.
Abstract: We have demonstrated stimulated emission in microring cavity formed by dye-doped polymer deposited on a gold wire. The mode structure suggests that the stimulated emission originates from surface plasmon polaritons propagating at the gold-polymer interface.
31 May 2009
TL;DR: In this article, a technique for sub-diffractional focusing in the far field of optical elements is proposed, which combines subwavelength analogs of Fresnel lenses and planar anisotropic metamaterials.
Abstract: We propose a technique for sub-diffractional focusing in the far field of optical elements. The method combines subwavelength analogs of Fresnel lenses and planar anisotropic metamaterials, used to generate and propagate sub-diffractional information, respectively.