Pseudo-refractive index and excitonic features of single layer CdSe/CdS core-shell nanoplatelet films.

Semiconductor CdSe/CdS core-shell nanoplatelets exhibit narrow and intense absorption and photoluminescence spectra in the visible range, which makes them suitable for numerous applications in optoelectronics. Of particular interest is the preparation and optical characterization of thin films with an accurately controlled amount of nanoplatelets. Here we report on the use of spectroscopic ellipsometry for investigating the optical properties of ultrathin films composed of a single layer of negatively charged CdSe/CdS core-shell nanoplatelets prepared by the electrostatic layer-by-layer deposition on SiO/Si substrates.

Publisher Correction: Tamm plasmon modes on semi-infinite metallodielectric superlattices.

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Tamm plasmon modes on semi-infinite metallodielectric superlattices.

We analyze the fundamental properties of optical waves referred to as Tamm plasmon modes (TPMs) which are tied to the interface of a semi-infinite two-phase metallodielectric superlattice with an arbitrary homogeneous capping medium. Such modes offer new ways of achieving high electromagnetic field localization and spontaneous emission enhancement in the vicinity of the interface in conjunction with absorption loss management, which is crucial for future applications. The homointerface, formed when the capping medium has the same permittivity as one of the superlattice constituents, is found to support a TPM whose dispersion overlaps the single-interface surface plasmon polariton (SPP) dispersion but which has a cut off at the topological transition point.

Electrically tunable terahertz polarization converter based on overcoupled metal-isolator-metal metamaterials infiltrated with liquid crystals.

Large birefringence and its electrical modulation by means of Fréedericksz transition makes nematic liquid crystals (LCs) a promising platform for tunable terahertz (THz) devices. The thickness of standard LC cells is in the order of the wavelength, requiring high driving voltages and allowing only a very slow modulation at THz frequencies. Here, we first present the concept of overcoupled metal-isolator-metal (MIM) cavities that allow for achieving simultaneously both very high phase difference between orthogonal electric field components and large reflectance.

Spectral and directional reshaping of fluorescence in large area self-assembled plasmonic-photonic crystals.

Spectral and directional reshaping of fluorescence from dye molecules embedded in self-assembled hybrid plasmonic-photonic crystals has been examined. The hybrid crystals comprise two-dimensional hexagonal arrays of dye-doped dielectric nanospheres, capped with silver semishells. Comparing the reshaped fluorescence spectra with measured transmission/reflection spectra and numerical calculations reveals that the spectral and directional reshaping of fluorescence is the result of its coupling to photonic crystal Bloch modes and to void plasmons localized inside the silver caps.

Nano- and microstructuring of graphene using UV-NIL.

In this work we demonstrate for the first time the micro- and nanostructuring of graphene by means of UV-nanoimprint lithography. Exfoliated graphene on SiO(2) substrates, as well as graphene deposited by chemical vapor deposition (CVD) on polycrystalline nickel and copper, and transferred CVD graphene on dielectric substrates, were used to demonstrate that our technique is suitable for large-area patterning (2 × 2 cm(2)) of graphene on various types of substrates. The demonstrated fabrication procedure of micrometer as well as nanometer-sized graphene structures with feature sizes down to 20 nm by a wafer-scale process opens up an avenue for the low-cost and high-throughput manufacturing of graphene-based optical and electronic applications.

Oblique incidence ellipsometric characterization and the substrate dependence of visible frequency fishnet metamaterials.

We use spectroscopic ellipsometry to investigate the angular-dependent optical modes of fishnet metamaterials fabricated by nanoimprint lithography. Spectroscopic ellipsometry is demonstrated as a fast and efficient method for metamaterial characterization and the measured polarization ratios significantly simplify the calibration procedures compared to reflectance and transmittance measurements. We show that the modes can be well identified by a combination of comparing different substrates and considering the angular dependence of the Wood's anomalies.

Controlling electromagnetic fields with graded photonic crystals in metamaterial regime.

Engineering of a refractive index profile is a powerful method for controlling electromagnetic fields. In this paper, we investigate possible realization of isotropic gradient refractive index media at optical frequencies using two-dimensional graded photonic crystals. They consist of dielectric rods with spatially varying radii and can be homogenized in broad frequency range within the lowest band.