Electromigrated electrical optical antennas for transducing electrons and photons at the nanoscale

• Arindam Dasgupta,
• Mickaël Buret,
• Nicolas Cazier,
• Marie-Maxime Mennemanteuil,
• Reinaldo Chacon,
• Kamal Hammani,
• Jean-Claude Weeber,
• Juan Arocas,
• Laurent Markey,
• Gérard Colas des Francs,
• Alexander Uskov,
• Igor Smetanin and
• Alexandre Bouhelier

Beilstein J. Nanotechnol. 2018, 9, 1964–1976, doi:10.3762/bjnano.9.187

• processing. We realize the implementation of tunneling antennas on a TiO2 waveguide through a multi-step process. First, a 85 to 110 nm thick titanium dioxide layer is deposited by physical vapor deposition on a clean glass substrate. Then, the Au backbone that will subsequently define the electrically

• electromigrating in situ the nanowire to create the optical tunneling gap antenna. Figure 6a,c,e illustrates the experiment with different waveguide geometries and gap orientations. In Figure 6a, the TiO2 waveguide is 85 nm thick and 1.5 μm wide, and the SEM image was taken before the electromigration of the

• gap at the center of the waveguide. Figure 6b,d,f shows false-color CCD images showing the distribution of the light radiated in the substrate when the tunneling junctions are biased by Vdc. The electrical operating conditions are reported in the images. In all these devices, light is most likely

Tunable fractional Fourier transform implementation of electronic wave functions in atomically thin materials

• Daniela Dragoman

Beilstein J. Nanotechnol. 2018, 9, 1828–1833, doi:10.3762/bjnano.9.174

• Schrödinger equation [11] to implement the FrFT of electron wave functions. In optics, the FrFT of order α of an incident optical field E(x,y) = E(x)exp(iky), which propagates with a propagation constant k along the y direction in a planar GRIN waveguide with refractive index n(x) = n0 − n1x2/2, and satisfies

• given length, the order of the FrFT at the output can be tuned by varying the potential energy, i.e., the parameters U0 and γ. The GRIN optical waveguide/electrostatic potential modulates periodically the optical field/quantum wave function, as can be seen from the matrix relating the transverse

• currents/signals from waveguide or sensor arrays [29][30][31] (to mention only a few references). Indeed, the inverse scattering problem has extensive applications in everyday life, so that retrieval algorithms exist or can be adapted for virtually any situation. Conclusion In conclusion, a parabolic

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• other hand, have orthogonally directed net dipole moments, but, as is the case with the radial mode, the electric field in each slot is directed normal to the long axis of slots, but each slot is not equally excited. An examination of the dispersion relations of a waveguide consisting of these three

• degeneracy of the dipole and radial modes of the slot structure have been broken due to coupling between the apertures. This is consistent with the dispersion relation for the corresponding waveguide modes (see Supporting Information File 1) indicating a zeroth order Fabry–Pérot resonance for the radial mode

Surface characterization of nanoparticles using near-field light scattering

• Eunsoo Yoo,
• Yizhong Liu,
• Chukwuazam A. Nwasike,
• Sebastian R. Freeman,
• Brian C. DiPaolo,
• Bernardo Cordovez and
• Amber L. Doiron

Beilstein J. Nanotechnol. 2018, 9, 1228–1238, doi:10.3762/bjnano.9.114

• using near-field light scattering. The local scattering intensity is correlated with the distance between the particle and waveguide, which is affected by the size of the particle (coating thickness) as well as the interactions between the particle and waveguide (related to the zeta potential of the

• iron oxide nanoparticles (IPC-SPIOs). Nanophotonic force microscopy pushes particles against a waveguide surface, optically trapping the particles by light confinement [10][19][20]. The evanescent fields are created by the waveguide, and there are four forces operating on the field: the gradient force

• of the waveguide is changed, which produces a local increase in intensity, and high-speed imaging of trapped nanoparticles allows for measurement of interactions between trapped nanoparticles and the waveguide. A higher intensity signal is created by a particle in close proximity to the waveguide

Near-field surface plasmon field enhancement induced by rippled surfaces

• Mario D’Acunto,
• Francesco Fuso,
• Ruggero Micheletto,
• Makoto Naruse,
• Francesco Tantussi and
• Maria Allegrini

Beilstein J. Nanotechnol. 2017, 8, 956–967, doi:10.3762/bjnano.8.97

• could also represent a sort of waveguide mode for the SPP propagation, the rough surface seems to have a leading role for the formation of the field enhancements in contrast to SPP propagation. A unique description of SPP propagation, QNMs in random nanogaps and localized plasmons is highly desirable

Flexible photonic crystal membranes with nanoparticle high refractive index layers

• Torben Karrock,
• Moritz Paulsen and
• Martina Gerken

Beilstein J. Nanotechnol. 2017, 8, 203–209, doi:10.3762/bjnano.8.22

• ; flexible membrane; nanostructure; photonic crystal; resonance shift; Introduction Photonic crystal slabs (also called resonance waveguide gratings) consist of a guiding layer with high refractive index on a nanostructured substrate. A subwavelength grating gives the incident light a lateral momentum and

• gratings properties, the waveguide properties, and the angle of incidence. Many different fabrication approaches have been presented and recent publications show high potential for future products, including multiparametric label-free biosensing [4], photonic crystal enhanced microscopy [5], single

• sensing [12]. N. L. Privorotskaya et al. [13] demonstrated a resonance shift of 4.53 nm per % strain and S. J. Foland and J.-B. Lee [14] measured 4.8 nm per % strain. The samples were stretched up to 3.75% and 5% strain, respectively. We previously identified cracking of continuous high-index waveguide

Sub-nanosecond light-pulse generation with waveguide-coupled carbon nanotube transducers

• Felix Pyatkov,
• Svetlana Khasminskaya,
• Vadim Kovalyuk,
• Frank Hennrich,
• Manfred M. Kappes,
• Gregory N. Goltsman,
• Wolfram H. P. Pernice and
• Ralph Krupke

Beilstein J. Nanotechnol. 2017, 8, 38–44, doi:10.3762/bjnano.8.5

• electrical signals into optical ones within a nanophotonic circuit. Here, we demonstrate that waveguide-integrated single-walled CNTs are promising high-speed transducers for light-pulse generation in the gigahertz range. Using a scalable fabrication approach we realize hybrid CNT-based nanophotonic devices

• ; Introduction Efficient transducers that allow converting electrical signals into optical ones and vice versa are essential ingredients for emerging applications in on-chip optoelectronic circuits. In particular, nanoscale transducers that can be seamlessly integrated into optical waveguide structures are

• needed to enable on-chip data communication in devices with small footprint. In this context carbon nanotubes (CNTs) have been identified as promising active components [1][2]. As a first step towards CNT-based optoelectronic photonic devices, light generation in waveguide-like electrodes [3] and optical

Grazing-incidence optical magnetic recording with super-resolution

• Gunther Scheunert,
• Sidney. R. Cohen,
• René Kullock,
• Ryan McCarron,
• Katya Rechev,
• Ifat Kaplan-Ashiri,
• Ora Bitton,
• Paul Dawson,
• Bert Hecht and
• Dan Oron

Beilstein J. Nanotechnol. 2017, 8, 28–37, doi:10.3762/bjnano.8.4

• during fabrication to assure the highest possible energy product. At the heart of HAMR devices is a near-field transducer (NFT): a device which consists of a light-capturing unit like a coupling grating, a waveguide structure and a surface plasmon resonator (SPR) positioned in immediate proximity to the

Precise in situ etch depth control of multilayered III−V semiconductor samples with reflectance anisotropy spectroscopy (RAS) equipment

• Ann-Kathrin Kleinschmidt,
• Lars Barzen,
• Johannes Strassner,
• Christoph Doering,
• Henning Fouckhardt,
• Wolfgang Bock,
• Michael Wahl and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2016, 7, 1783–1793, doi:10.3762/bjnano.7.171

• the first time the highly etch depth sensitive lithographic process to form a film lens on the waveguide ridge of a broad area laser (BAL) is presented. This example elucidates the benefits of the method in semiconductor device fabrication and also suggests how to fulfill design requirements for the

• remaining layer thicknesses. Thus the accuracy stated earlier can be verified experimentally, for the first time. The benefit of dry-etch control with RAS is demonstrated for a realistic semiconductor device fabrication process, which is highly etch depth sensitive: i.e., the fabrication of a film waveguide

• sequence of a semiconductor laser, mainly consisting of several layers of Ga(As)Sb quantum dots (QD) (as active material) embedded in GaAs, surrounded by n- and p-doped layers of Al0.5Ga0.5As (for the diode and waveguide structure), has been grown on an n-doped GaAs substrate (called sample type B, for

Surface-enhanced infrared absorption studies towards a new optical biosensor

• Lothar Leidner,
• Julia Stäb,
• Jennifer T. Adam and
• Günter Gauglitz

Beilstein J. Nanotechnol. 2016, 7, 1736–1742, doi:10.3762/bjnano.7.166

• to signal enhancement is demonstrated by the surface-enhanced infrared attenuated infrared total reflection (SEIRA-ATR) set-up used by López-Lorente and co-workers [13]. Gold nanoparticles were directly synthesized within a liquid cell of an ATR unit and deposited on the surface of the ATR waveguide

• . The deposition of the water molecules leads to an increase of water absorption features due to adsorption of water molecules to the nanoparticle layer on top of the ATR waveguide. In the current work, water absorption spectra have been studied under the influence of silver nanoparticles present in an

• different. The ATR spectra are caused by absorption in the zone of the evanescent field above the ATR waveguide. In the case of the RIfS sensor, the interesting region is around the polymer–water interface. According to the Fresnel equations, a part of the radiation is reflected, the rest is transmitted

Highly compact refractive index sensor based on stripe waveguides for lab-on-a-chip sensing applications

• Chamanei Perera,
• Kristy Vernon,
• Elliot Cheng,
• Juna Sathian,
• Esa Jaatinen and
• Timothy Davis

Beilstein J. Nanotechnol. 2016, 7, 751–757, doi:10.3762/bjnano.7.66

• ]. MZIs can be designed to be wavelength specific and more compact using waveguide structures. Vernon et al. proposed a compact interferometer design using stripe waveguide coupling to measure the change in the refractive index of a sample using the change in the output intensity [19]. The stripe

• paper, we report the realisation of a refractive index sensor based on stripe waveguide coupling (see Figure 1). The structure is similar to the structure proposed by Vernon et al. [19] but without the output coupling arm, thus reducing the overall size of the device. The sample window was etched on top

• outer arms (i.e., the lengths of the arms are determined by the coupling length of the system). A schematic of the interferometer design is given in Figure 1. Results and Discussion Theory For the MZI based on stripe waveguides, the waveguide is required to support a single LRSPP mode (ssb0) at 633 nm

Fabrication and properties of luminescence polymer composites with erbium/ytterbium oxides and gold nanoparticles

• Julia A. Burunkova,
• Ihor Yu. Denisiuk,
• Dmitri I. Zhuk,
• Lajos Daroczi,
• Attila Csik,
• István Csarnovics and
• Sándor Kokenyesi

Beilstein J. Nanotechnol. 2016, 7, 630–636, doi:10.3762/bjnano.7.55

• ]. Planar waveguide amplifiers on the basis of Er-containing nanocomposites are actively investigated as well (see for example [2], where a PMMA-based, Yb2O3/Er2O3-containing polymer nanocomposite waveguide optical amplifier was demonstrated). This material ensures the functioning of the amplifier with an

• interaction length of about 5 mm, which is sufficient for applications in integrated optics. It is an important task to create such functional materials with high concentrations of Er for waveguides of integrated optical systems that can realize amplification in a few millimeters long waveguide instead of

Novel roles for well-known players: from tobacco mosaic virus pests to enzymatically active assemblies

• Claudia Koch,
• Fabian J. Eber,
• Carlos Azucena,
• Alexander Förste,
• Stefan Walheim,
• Thomas Schimmel,
• Alexander M. Bittner,
• Holger Jeske,
• Hartmut Gliemann,
• Sabine Eiben,
• Fania C. Geiger and
• Christina Wege

Beilstein J. Nanotechnol. 2016, 7, 613–629, doi:10.3762/bjnano.7.54

• microdisc resonators, was readily detectable through changes in the effective refractive index of the waveguide setup and the concomitant shifts in the resonant wavelength of the sensor cavity, with signal amplification through label-free enzyme-linked immunosorbent assay (ELISA) [134]. The sensor system

• -directing RNA. After decoration with bioactive molecules, such arrays ensure stable interlinkage of technical surfaces and biological effector molecules. Adapted with permission from [54], copyright (2011) American Chemical Society. B: Engineered TMV-like particles coating the waveguide setup of an optical

Linear and nonlinear optical properties of hybrid metallic–dielectric plasmonic nanoantennas

• Mario Hentschel,
• Bernd Metzger,
• Bastian Knabe,
• Karsten Buse and
• Harald Giessen

Beilstein J. Nanotechnol. 2016, 7, 111–120, doi:10.3762/bjnano.7.13

• , Utikal et al. [61] buried gold gratings within dielectric waveguides consisting of alumina, indium tin oxide, or tungsten trioxide, respectively, and studied the third harmonic spectra. They found that the overall signal is generated not only by the gold itself, but by the dielectric waveguide as well

• system can indeed be decoupled. In all these cases, the cause for this deviation is actually the contribution of a dielectric medium, e.g., a waveguide. Utikal and co-workers demonstrated that the nonlinear response of different plasmon waveguide hybrid systems can be different in spite of nearly

• identical linear optical properties [61]. In this case, energy is transferred from the “bright” plasmonic resonance to the “dark” waveguide mode. The exact fraction of energy stored in the plasmon and waveguide modes is not encoded in the far-field spectra. Additionally, both systems have entirely different

Mapping bound plasmon propagation on a nanoscale stripe waveguide using quantum dots: influence of spacer layer thickness

• Chamanei S. Perera,
• Alison M. Funston,
• Han-Hao Cheng and
• Kristy C. Vernon

Beilstein J. Nanotechnol. 2015, 6, 2046–2051, doi:10.3762/bjnano.6.208

• 4072, QLD, Australia 10.3762/bjnano.6.208 Abstract In this paper we image the highly confined long range plasmons of a nanoscale metal stripe waveguide using quantum emitters. Plasmons were excited using a highly focused 633 nm laser beam and a specially designed grating structure to provide stronger

• incoupling to the desired mode. A homogeneous thin layer of quantum dots was used to image the near field intensity of the propagating plasmons on the waveguide. We observed that the photoluminescence is quenched when the QD to metal surface distance is less than 10 nm. The optimised spacer layer thickness

• for the stripe waveguides was found to be around 20 nm. Authors believe that the findings of this paper prove beneficial for the development of plasmonic devices utilising stripe waveguides. Keywords: photoluminescence; plasmonics; quantum dot; spacer layer; stripe waveguide; Introduction Plasmons

Attenuation, dispersion and nonlinearity effects in graphene-based waveguides

• Almir Wirth Lima Jr.,
• João Cesar Moura Mota and
• Antonio Sergio Bezerra Sombra

Beilstein J. Nanotechnol. 2015, 6, 1221–1228, doi:10.3762/bjnano.6.125

• highly relevant since they can be applied to other nanophotonic devices, for example, filters, modulators, antennas, switches and other devices. Keywords: graphene; nanophotonics; waveguide; Introduction The production of smaller yet more simple and efficient electronic and photonic devices is the

• nanophotonics waveguides, this study was focused on the simulation and analysis of the attenuation, dispersion and nonlinear effects occurring in signals propagating through a graphene-based waveguide. We considered a graphene nanoribbon located between similar dielectric layers, as will be described further

• present in the waveguide. Previous studies showed that in a graphene nanoribbon of width <50 nm, there exists only a single mode (fundamental mode) [3]. However, due to finite-size effects, when W < 10 nm, the classical theory can no longer predict the behavior of GSPPs in a graphene nanoribbon [8

Size-dependent density of zirconia nanoparticles

• Agnieszka Opalinska,
• Iwona Malka,
• Wojciech Dzwolak,
• Tadeusz Chudoba,
• Adam Presz and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2015, 6, 27–35, doi:10.3762/bjnano.6.4

• those of conventional micrometer-sized ZrO2. These differences are the result of the unusual properties which occur at the nanoscale and the surface phenomena [8][9][10]. Using nano-ZrO2 as a waveguide host matrix material for light and optical amplification is promising due to its very good chemical

Mechanical properties of sol–gel derived SiO₂ nanotubes

• Boris Polyakov,
• Mikk Antsov,
• Sergei Vlassov,
• Leonid M Dorogin,
• Mikk Vahtrus,
• Roberts Zabels,
• Sven Lange and
• Rünno Lõhmus

Beilstein J. Nanotechnol. 2014, 5, 1808–1814, doi:10.3762/bjnano.5.191

• environmentally sensitive materials [4][5], biological and biosensing applications [6][7][8], waveguide optics and photonics [9][10][11][12]. However, only a few publications were dedicated to the investigation of the mechanical properties of one-dimensional silica nanostructures, and even less to the ones

Pyrite nanoparticles as a Fenton-like reagent for in situ remediation of organic pollutants

• Carolina Gil-Lozano,
• Elisabeth Losa-Adams,
• Alfonso F.-Dávila and
• Luis Gago-Duport

Beilstein J. Nanotechnol. 2014, 5, 855–864, doi:10.3762/bjnano.5.97

• decoloration (degradation) of CuPc was monitored by tracking the absorbance at 630 nm, using fiber optic UV–vis spectrometry (Black-comet, Stellarnet). A liquid waveguide capillary flow cell (LWCC; path length: 250 cm; WPI), was connected to the batch reactor by a peristaltic pump (masterflex pump system, Cole

• 27 h. b) UV-vis spectrum of the peak at 5.7 minutes (λmax: 217 nm). Proposed reaction mechanisms for the generation of H2O2 and for the oxidative degradation of CuPc by OH•. Experimental set-up using a liquid waveguide capillary flow cell (LWCC). Acknowledgements This research was funded by the

An ultrasonic technology for production of antibacterial nanomaterials and their coating on textiles

• Anna V. Abramova,
• Vladimir O. Abramov,
• Aharon Gedanken,
• Ilana Perelshtein and
• Vadim M. Bayazitov

Beilstein J. Nanotechnol. 2014, 5, 532–536, doi:10.3762/bjnano.5.62

• into the reactor. The upper electrode was simultaneously an emitter of the oscillation system, which contained also a waveguide and an ultrasonic transducer. An ultrasonic generator (4) powered the transducer. The electrodes were connected to the power supply of the sonoplasma discharge (5). The setup

• also contained rod electrodes (3) to initiate the arc discharge, which were connected to their own power supply (7). Gaseous reaction products were accumulated in a special gas collector (6). The output of acoustical power of the system was 2.0 kW, the working frequency of the transducer and waveguide

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

• Jinzhang Liu,
• Marco Notarianni,
• Llew Rintoul and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 485–493, doi:10.3762/bjnano.5.56

• synthesis methods and applications. ZnO is a multifunctional material with semiconducting, photonic, and piezoelectric properties. Potential applications of ZnO 1D nanostructures include gas sensor [1], transistor [2], light-emitting device [3], optical waveguide [4], nanolaser [5], and piezoelectric power

• ray in ZnO is about 30 °C. Due to the waveguide effect partial photons would propagate along the nanorod axis direction. Hence inside the nanorod light rays refracted to top upper facet have contribution to the PL signal (Figure 6c). Light rays with different polarizations have different transmittance

• stronger PL signal can be collected due to the waveguide effect and Fabry–Pérot type resonances or even lasing can be achieved. Conclusion In summary, we have demonstrated the encapsulation of nanoparticles into single crystal ZnO nanorods by exploiting crystal growth. Nanodiamonds and polymer nanobeads

k-space imaging of the eigenmodes of sharp gold tapers for scanning near-field optical microscopy

• Martin Esmann,
• Simon F. Becker,
• Bernard B. da Cunha,
• Jens H. Brauer,
• Ralf Vogelgesang,
• Petra Groß and
• Christoph Lienau

Beilstein J. Nanotechnol. 2013, 4, 603–610, doi:10.3762/bjnano.4.67

• light down to volumes well below the classical diffraction limit [5][6]. In particular, it has been predicted that SPP wavepackets may be localized both in space and time when they are launched onto a tapered metallic waveguide, e.g., a conical tip with a nanometer-sized apex and sufficiently small

• of a tapered wire In order to describe the process of linear SPP propagation on the SNOM probe in the framework of classical electrodynamics, it is useful to expand the SPP wavepacket in terms of orthonormal eigenmodes at any point along the waveguide. The concept of adiabatic nanofocusing assumes

• that the diameter of a tapered waveguide varies only slowly over the distance of one wavelength of the guided SPP. Therefore, a proper local set of eigenmodes is well approximated by the eigenmodes of an infinitely long waveguide having the local diameter of the taper. For a cylindrical metal wire

Grating-assisted coupling to nanophotonic circuits in microcrystalline diamond thin films

• Patrik Rath,
• Svetlana Khasminskaya,
• Christoph Nebel,
• Christoph Wild and
• Wolfram H.P. Pernice

Beilstein J. Nanotechnol. 2013, 4, 300–305, doi:10.3762/bjnano.4.33

• waveguide fabricated this way is shown in Figure 1b. Focussed ion beam (FIB) milling is used to cut through a waveguide cross-section, which is the reason for the line features at the edge of the waveguide. The FIB image reveals that the sidewalls resulting from the etching are near vertical, illustrating

• that the etch recipe is indeed highly anisotropic. Also visible in the image is the residual e-beam resist (labelled HSQ for Hydrogen silsesquioxane) on top of the waveguide. Design of focussing grating couplers We fabricate nanophotonic waveguides with a width of 1000 nm using the procedure outlined

• above. Here we employ partially etched ridge waveguides as shown in the image in Figure 1b. By using such a waveguide geometry, the optical mode is confined more deeply into the diamond thin film compared to fully etched strip waveguides. This way, scattering effects due to the remaining surface

Diamond nanophotonics

• Katja Beha,
• Helmut Fedder,
• Marco Wolfer,
• Merle C. Becker,
• Petr Siyushev,
• Mohammad Jamali,
• Anton Batalov,
• Christopher Hinz,
• Jakob Hees,
• Lutz Kirste,
• Harald Obloh,
• Etienne Gheeraert,
• Boris Naydenov,
• Ingmar Jakobi,
• Florian Dolde,
• Sébastien Pezzagna,
• Daniel Twittchen,
• Matthew Markham,
• Daniel Dregely,
• Harald Giessen,
• Jan Meijer,
• Fedor Jelezko,
• Christoph E. Nebel,
• Rudolf Bratschitsch,
• Alfred Leitenstorfer and
• Jörg Wrachtrup

Beilstein J. Nanotechnol. 2012, 3, 895–908, doi:10.3762/bjnano.3.100

• due to the total internal reflection at the pillar sidewalls [13][14]. Due to the waveguide nature of pillar resonators, the photoluminescence emission is strongly directional, which results in the efficient collection of radiation with a microscope objective. A broadband light transmission

• of these resonances (Figure 8d) are calculated based on an effective-waveguide model. The theoretical results are in excellent agreement with the values obtained by the experiment. The simulations also yield the spatial mode patterns depicted in Figure 8c. The recorded CCD image of the

Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor

• Wolfgang Molnar,
• Alois Lugstein,
• Tomasz Wojcik,
• Peter Pongratz,
• Norbert Auner,
• Christian Bauch and
• Emmerich Bertagnolli

Beilstein J. Nanotechnol. 2012, 3, 564–569, doi:10.3762/bjnano.3.65

• perchlorinated polysilanes an industrial microwave device (MX 4000, Muegge Electronics GmbH), connected to a rectangular waveguide that leads into a reaction chamber, was used. The reactor itself consisted of a quartz-glass tube, inserted into the microwave cavity, with the axis of the waveguide being