Optically and electrically driven nanoantennas

• Monika Fleischer,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2020, 11, 1542–1545, doi:10.3762/bjnano.11.136

• ultrahigh sensitivity sensing the central feature for tightly confining and enhancing the optical near-field is a narrow gap between two metallic nanoparticles or tips. Creating such gaps to obtain a controlled distribution of hotspots, for example, on a chip, is no trivial task. This has been pursued using

Enhancement of X-ray emission from nanocolloidal gold suspensions under double-pulse excitation

• Wei-Hung Hsu,
• Frances Camille P. Masim,
• Armandas Balčytis,
• Hsin-Hui Huang,
• Tetsu Yonezawa,
• Aleksandr A. Kuchmizhak,
• Saulius Juodkazis and
• Koji Hatanaka

Beilstein J. Nanotechnol. 2018, 9, 2609–2617, doi:10.3762/bjnano.9.242

• solutions maximizes the volume of εr-near-zero (ENZ) regions and overlaps with the focal volume of the main pulse. Those ENZ regions are responsible for the most efficient energy deposition via absorption and define the transition of the propagating light to the ENZ surface (an optical near-field). This

Dumbbell gold nanoparticle dimer antennas with advanced optical properties

• Janning F. Herrmann and
• Christiane Höppener

Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205

• asymmetric gold nanoparticle antennas (AuNPs) with improved optical near-field properties based on the formation of sub-nanometer size gaps, which are suitable for studying matter with high-resolution and single molecule sensitivity. These dumbbell antennas are characterized in regard to their far-field and

Optical near-field mapping of plasmonic nanostructures prepared by nanosphere lithography

• Gitanjali Kolhatkar,
• Alexandre Merlen,
• Jiawei Zhang,
• Chahinez Dab,
• Gregory Q. Wallace,
• François Lagugné-Labarthet and
• Andreas Ruediger

Beilstein J. Nanotechnol. 2018, 9, 1536–1543, doi:10.3762/bjnano.9.144

• Department and Centre for Materials and Biomaterials, 1151 Richmond Street, London, ON, N6A5B7, Canada 10.3762/bjnano.9.144 Abstract We introduce a simple, fast, efficient and non-destructive method to study the optical near-field properties of plasmonic nanotriangles prepared by nanosphere lithography

• : apertureless scanning near-field optical microscopy; diffuse signal; nanosphere lithography; photomultiplier tube; plasmonic nanostructures; Introduction SNOM (scanning near-field optical microscopy) is an imaging technique based on an optical near-field probe for high spatial resolution [1][2]. A version of

• near-field contribution coming from the sample itself. As can be seen in Figure 2a, the complex interferometric background is also present with the gold nanotriangles. This feature prevents the direct observation of their optical near-field contribution. To extract this near-field signal from the

Angstrom-scale flatness using selective nanoscale etching

• Takashi Yatsui,
• Hiroshi Saito and
• Katsuyuki Nobusada

Beilstein J. Nanotechnol. 2017, 8, 2181–2185, doi:10.3762/bjnano.8.217

• ; optical near-field; wet etching; Introduction The use of optical near-fields (ONFs) has contributed to the progress of nanoscale optical measurements [1], nanoscale fabrication [2], and photonic devices [3] below the diffraction limit of light. Recent ONF studies have exploited non-uniformity to realize

Surface improvement of organic photoresists using a near-field-dependent etching method

• Felix J. Brandenburg,
• Tomohiro Okamoto,
• Hiroshi Saito,
• Benjamin Leuschel,
• Olivier Soppera and
• Takashi Yatsui

Beilstein J. Nanotechnol. 2017, 8, 784–788, doi:10.3762/bjnano.8.81

• carefully chosen to be below the direct O2 dissociation energy. Previous theories suggest localized optical near-fields can cause two-step excitation via vibrational levels in molecules [13]. In theory, the localized optical near-field has a nonuniform field distribution and thus can activate the dipole

The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

• Yevgeniy R. Davletshin and
• J. Carl Kumaradas

Beilstein J. Nanotechnol. 2016, 7, 869–880, doi:10.3762/bjnano.7.79

• the picosecond regime is highly dependent on the optical near-field enhancement instead of nanoparticle size and absorption cross-section. The findings of this study will help in LIB-related fields to advance the understanding of nanoparticle–laser interactions, which will lead to the better design of

• element method. The thresholds of optical breakdown for off- and on-resonance irradiated gold nanosphere monomers were compared against nanosphere dimers, trimers, and gold nanorods with the same overall size and aspect ratio. The optical breakdown thresholds had a stronger dependence on the optical near

• -field enhancement than on the mass or absorption cross-section of the nanostructure. These findings can be used to advance the nanoparticle-based nanoscale manipulation of matter. Keywords: electron plasma; finite element method; optical breakdown; plasmon coupling; plasmonic nanoparticles

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

• Kai Braun,
• Xiao Wang,
• Andreas M. Kern,
• Hilmar Adler,
• Heiko Peisert,
• Thomas Chassé,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2015, 6, 1100–1106, doi:10.3762/bjnano.6.111

• scattered to the far field. While the gap modes plasmon resonance is very broad, exhibiting a quality factor of only Q ≈ 15, the resonantly stored energy in the optical near field in the gap is extremely well localized, in a volume having an upper limit of approximately 4 × 4 × 1 nm3 (see Figure S8

Controlling the optical and structural properties of ZnS–AgInS₂ nanocrystals by using a photo-induced process

• Takashi Yatsui,
• Fumihiro Morigaki and
• Tadashi Kawazoe

Beilstein J. Nanotechnol. 2014, 5, 1767–1773, doi:10.3762/bjnano.5.187

• the control of its size to ensure that the quantized energy levels are resonant to facilitate an efficient optical near-field interaction. The solution process could be a promising process for this purpose because it can easily regulate the size and shape by controlling the growth kinetics [10]. It

Observation and analysis of structural changes in fused silica by continuous irradiation with femtosecond laser light having an energy density below the laser-induced damage threshold

• Wataru Nomura,
• Tadashi Kawazoe,
• Takashi Yatsui,
• Makoto Naruse and
• Motoichi Ohtsu

Beilstein J. Nanotechnol. 2014, 5, 1334–1340, doi:10.3762/bjnano.5.146

• performing optical near-field etching on a substrate prepared under the same conditions as sample A. The samples A and B had a minimum average surfaces roughnesses Ra of 0.20 nm and 0.13 nm, respectively [12]. Since we employed a continuous-wave laser with the wavelength of 532 nm and power of 2 W for

• optical near-field etching, the sample B did not have any laser-induced damage or degradation caused by this preparation. Optical near-field etching is a surface planarization technique for selectively removing only minute protrusions in the surface of a substrate, and can flatten the planer substrate

Optical near-fields & nearfield optics

• Alfred J. Meixner and
• Paul Leiderer

Beilstein J. Nanotechnol. 2014, 5, 186–187, doi:10.3762/bjnano.5.19

• , because they support surface plasmons, i.e., collective excitations of the electron gas, which couple strongly to light. As a result, the optical near-field around such plasmonic structures can be enhanced by orders of magnitude compared to the incident light intensity, and can be localized in “hot spots

• localization of distinct building blocks of supramolecular structures below the usual optical resolution. This is facilitated by using the optical near-field around a sharp dielectric AFM tip to excite the fluorescent molecules – a metallic tip would quench the fluorescence. The optical near-fields of

• and nanotechnology, since many of the nanostructures of interest are distinctly smaller than this limit of a few hundred nanometers. Fortunately, this restriction can be overcome, if one does not rely on focusing with lenses and mirrors in the optical far-field, but rather exploits the optical near

Challenges in realizing ultraflat materials surfaces

• Takashi Yatsui,
• Wataru Nomura,
• Fabrice Stehlin,
• Olivier Soppera,
• Makoto Naruse and
• Motoichi Ohtsu

Beilstein J. Nanotechnol. 2013, 4, 875–885, doi:10.3762/bjnano.4.99

• nanophotonics in the next section. Optical near field: dressed photon–phonon Near-field optics has made it possible to reduce the size of photonic devices to the sub-wavelength scale or smaller [17]. In particular, nanoscale photonic devices such as AND-gates, NOT-gates, and focusing devices have been developed

• that utilize the optical near field generated in nanoscale semiconductor quantum structures and the dipole-forbidden near-field energy transfer. Moreover, near-field optics has been used to fabricate nanoscale structures beyond the diffraction limit of light. For example, photolithography has been used

Probing the plasmonic near-field by one- and two-photon excited surface enhanced Raman scattering

• Katrin Kneipp and
• Harald Kneipp

Beilstein J. Nanotechnol. 2013, 4, 834–842, doi:10.3762/bjnano.4.94

• particularly also for optical spectroscopy. Surface enhanced Raman signatures of single molecules can provide us with important information about the optical near-field. We discuss one- and two-photon excited surface enhanced Raman scattering at the level of single molecules as a tool for probing the plasmonic

• -resolutions and even below [15][16][17][18][19]. We have applied EELS for probing the local distribution of plasmonic fields at nanometer scale for nanoaggregates formed by silver particles [18]. Here we discuss experiments for probing the optical near-field of silver nanoaggregates by using one- and two

• enhancement factors larger than 109 [50]. Conclusion SERS experiments at the single molecule level open up interesting ways for probing the optical near-field in the hottest hot spots of plasmonic nanostructures. Our studies identify field enhancement factors on the order of 103 with corresponding

Mapping of plasmonic resonances in nanotriangles

• Simon Dickreuter,
• Julia Gleixner,
• Andreas Kolloch,
• Johannes Boneberg,
• Elke Scheer and
• Paul Leiderer

Beilstein J. Nanotechnol. 2013, 4, 588–602, doi:10.3762/bjnano.4.66

• the near field of a sample, which is illuminated conventionally [8][9][10]. A related approach is to use a very fine metal or dielectrical tip as a scatterer in the vicinity of the optical near field of the sample [11][12][13]. Another method for mapping near fields is photoemission electron

• of the optical near-field distribution. In order to address this problem we have investigated so-called bow-tie antennas, consisting of two triangles as shown in Figure 3d. Figure 13a shows the region between such a bow-tie antenna with a gap distance of 30 nm, after it has been irradiated with a

Plasmonic oligomers in cylindrical vector light beams

• Mario Hentschel,
• Jens Dorfmüller,
• Harald Giessen,
• Sebastian Jäger,
• Andreas M. Kern,
• Kai Braun,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2013, 4, 57–65, doi:10.3762/bjnano.4.6

• can be utilized in order to fabricate the structures. Nearly every manipulation in the design of the cluster can be easily implemented. Figure 5b depicts a collection of SEM micrographs that demonstrate our ability to create nearly every arrangement imaginable [22][23][24][25][26]. The optical near

• -field microscope The studies of the optical behavior of the plasmonic oligomers with focused radially and azimuthally polarized laser beams were performed on home-built combined near-field scanning and confocal microscopes. The exciting laser is in both cases a 632.8 nm HeNe laser, where the beam is

Nano-FTIR chemical mapping of minerals in biological materials

• Sergiu Amarie,
• Paul Zaslansky,
• Yusuke Kajihara,
• Erika Griesshaber,
• Wolfgang W. Schmahl and
• Fritz Keilmann

Beilstein J. Nanotechnol. 2012, 3, 312–323, doi:10.3762/bjnano.3.35

• osteopathies. Keywords: biomineralization; chemical mapping; infrared spectroscopy; nanocrystals; optical near-field microscopy; Introduction Fourier-transform infrared spectroscopy (FTIR) [1] is a standard tool in chemical analysis. It can identify virtually any substance through the "fingerprint" of the