Enhancing mechanical properties of chitosan/PVA electrospun nanofibers: a comprehensive review

• Nur Areisman Mohd Salleh,
• Amalina Muhammad Afifi,
• Fathiah Mohamed Zuki and
• Hanna Sofia SalehHudin

Beilstein J. Nanotechnol. 2025, 16, 286–307, doi:10.3762/bjnano.16.22

• approaches with distinct fiber-producing capabilities such as centrifugal electrospinning, alternating current electrospinning, near-field electrospinning, multinozzle electrospinning, and needleless electrospinning. Other improvement efforts include modifications on the solution or melts used for

Investigations on the optical forces from three mainstream optical resonances in all-dielectric nanostructure arrays

• Guangdong Wang and
• Zhanghua Han

Beilstein J. Nanotechnol. 2023, 14, 674–682, doi:10.3762/bjnano.14.53

• interact directly with electromagnetic waves and is often masked by electric dipoles (EDs) or magnetic dipoles (MDs) with stronger responses. However, the TD has a unique current distribution, which can generate a strong near-field localization effect, so it has broad application scenarios [8]. The anapole

• forces on these spheres placed within the near field of these modes are calculated, analyzed, and compared. We found that the optical force applied on the same PS sphere by the quasi-BIC mode under the same excitation power is about three orders of magnitude larger than those from the other two modes

Observation of multiple bulk bound states in the continuum modes in a photonic crystal cavity

• Rui Chen,
• Yi Zheng,
• Xingyu Huang,
• Qiaoling Lin,
• Chaochao Ye,
• Meng Xiong,
• Martijn Wubs,
• Yungui Ma,
• Minhao Pu and
• Sanshui Xiao

Beilstein J. Nanotechnol. 2023, 14, 544–551, doi:10.3762/bjnano.14.45

• direction [30] in BIC devices. In our experiment, the mode indices are not identified. They could be identified by observing far-field radiation patterns of the modes [30]. Also, near-field patterns of modes could be obtained by near-field microscopy [44]. Both methods need a precise optical setup and an

• all bulk modes. (d) The near-field H field intensity distribution of modes M11 to M44. The yellow dashed squares indicate the boundary of region A. Fabricated samples and optical setup. (a) Optical and scanning electron microscopy images of fabricated samples, scale bar: 10 μm. (b) Diagram of the

Plasmonic nanotechnology for photothermal applications – an evaluation

• A. R. Indhu,
• L. Keerthana and
• Gnanaprakash Dharmalingam

Beilstein J. Nanotechnol. 2023, 14, 380–419, doi:10.3762/bjnano.14.33

The steep road to nonviral nanomedicines: Frequent challenges and culprits in designing nanoparticles for gene therapy

• Yao Yao,
• Yeongun Ko,
• Grant Grasman,
• Jeffery E. Raymond and
• Joerg Lahann

Beilstein J. Nanotechnol. 2023, 14, 351–361, doi:10.3762/bjnano.14.30

• , in the case of large molecules (such as plasmids) in smaller particles, significant deviations from this trend can be observed. To better understand the per-particle variations in payload, high-resolution microscopy, such as total internal reflection fluorescence spectroscopy, near-field scanning

Characterisation of a micrometer-scale active plasmonic element by means of complementary computational and experimental methods

• Ciarán Barron,
• Giulia Di Fazio,
• Samuel Kenny,
• Silas O’Toole,
• Robin O’Reilly and
• Dominic Zerulla

Beilstein J. Nanotechnol. 2023, 14, 110–122, doi:10.3762/bjnano.14.12

• future photonic devices. This element operates by modulating optical constants in a localised fashion, thereby providing an external control over the strength of the electromagnetic near field above the element as well as its far-field response. A dual experimental approach is employed in tandem with

• peaks indicates the ability to maximise the modulation of the element’s optical response. While the classical SPR response integrates over the whole illuminated area, the LIA curve extracts the changes in reflectivity localised to the active element. This leads to a modulated local near field, which has

• method therefore investigates the thermal response of this active plasmonic element at a high spatial resolution. Knowledge of the distribution leads to predictions on how the near field will be locally affected, which is key for understanding the behaviour of the active plasmonic element. The heating

Double-layer symmetric gratings with bound states in the continuum for dual-band high-Q optical sensing

• Chaoying Shi,
• Jinhua Hu,
• Xiuhong Liu,
• Junfang Liang,
• Jijun Zhao,
• Haiyan Han and
• Qiaofen Zhu

Beilstein J. Nanotechnol. 2022, 13, 1408–1417, doi:10.3762/bjnano.13.116

• a wide resonance in the double-layer gratings for a given cavity length h. Without external driving sources, the two resonance amplitudes A = (A1,A2)T in the DLSG structure evolve in time as i∂A/∂t = HA with Hamiltonian [51][52][53]: where κ is the near-field coupling between the two modes, ω0 and

Studies of probe tip materials by atomic force microscopy: a review

• Ke Xu and
• Yuzhe Liu

Beilstein J. Nanotechnol. 2022, 13, 1256–1267, doi:10.3762/bjnano.13.104

• nanowires is directly coupled to the preparation of the probe, and the traditional method of fiber erosion across the film is more straightforward. The preparation of the probe can be directly used as a scanning near-field optical microscope scanning needle tip. Moreover, the probe prepared by this method

A super-oscillatory step-zoom metalens for visible light

• Yi Zhou,
• Chao Yan,
• Peng Tian,
• Zhu Li,
• Yu He,
• Bin Fan,
• Zhiyong Wang,
• Yao Deng and
• Dongliang Tang

Beilstein J. Nanotechnol. 2022, 13, 1220–1227, doi:10.3762/bjnano.13.101

• spatial resolution of λ/5 [3]. However, it requires additional designed illumination patterns and image reconstruction. Near-field scanning optical microscopy can achieve super-resolution imaging by detecting surface evanescent fields of objects [4]. Near-field focusing lenses [5] based on surface

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication

• Victor Deinhart,
• Lisa-Marie Kern,
• Jan N. Kirchhof,
• Sabrina Juergensen,
• Joris Sturm,
• Enno Krauss,
• Thorsten Feichtner,
• Sviatoslav Kovalchuk,
• Michael Schneider,
• Dieter Engel,
• Bastian Pfau,
• Bert Hecht,
• Kirill I. Bolotin,
• Stephanie Reich and
• Katja Höflich

Beilstein J. Nanotechnol. 2021, 12, 304–318, doi:10.3762/bjnano.12.25

• decay of the plasmonic near field. Hence, a nanopatterning approach that is able to realize sub-10 nm gaps in a reproducible manner is highly desired. He ion beam milling already demonstrated these capabilities in the fabrication of strongly coupled dimers with gap distances of less than 6 nm [62][63

Numerical analysis of vibration modes of a qPlus sensor with a long tip

• Kebei Chen,
• Zhenghui Liu,
• Yuchen Xie,
• Chunyu Zhang,
• Gengzhao Xu,
• Wentao Song and
• Ke Xu

Beilstein J. Nanotechnol. 2021, 12, 82–92, doi:10.3762/bjnano.12.7

• resolution and near-field optical images were obtained in liquid environments [15][18][19]. For some applications, it is required that the tip is not perpendicular to the prong of the tuning fork [20][21]. The advantage of a qPlus sensor with a long tilted tip (Figure 1) is that forces in multiple directions

Nanomechanics of few-layer materials: do individual layers slide upon folding?

• Ronaldo J. C. Batista,
• Rafael F. Dias,
• Ana P. M. Barboza,
• Alan B. de Oliveira,
• Taise M. Manhabosco,
• Thiago R. Gomes-Silva,
• Matheus J. S. Matos,
• Andreij C. Gadelha,
• Cassiano Rabelo,
• Luiz G. L. Cançado,
• Ado Jorio,
• Hélio Chacham and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2020, 11, 1801–1808, doi:10.3762/bjnano.11.162

• any 2D material and not restricted to talc. This hypothesis was investigated employing a near-field tip-enhanced Raman spectroscopy (TERS) setup [36][37] that can probe strain variations across the edge of a folded graphene flake of 5 nm thickness (see Supporting Information File 1, section “Near

• to AFM measurements on a fold in an eleven layers thick graphene flake. Supporting Information Supporting information features the theoretical models for deposited and compressed folded edges, the experimental methods (including sample preparation, SPM characterization and near-field tip-enhanced

• -field tip-enhanced Raman spectroscopy”). Our TERS measurements (see Supporting Information File 1) do not show significant changes in the G band of the Raman spectra in the folded region. This either indicates a negligible strain in the fold region, or a combination of small compressive and tesile

Mapping of integrated PIN diodes with a 3D architecture by scanning microwave impedance microscopy and dynamic spectroscopy

• Rosine Coq Germanicus,
• Peter De Wolf,
• Florent Lallemand,
• Catherine Bunel,
• Serge Bardy,
• Hugues Murray and
• Ulrike Lüders

Beilstein J. Nanotechnol. 2020, 11, 1764–1775, doi:10.3762/bjnano.11.159

• electromagnetically shielded and electrically conductive tip [20]. The sMIM mode is based on the combination of the AFM capabilities, in terms of imaging with a high spatial resolution and versatility, and the near-field interaction of an incident microwave with the studied material. From the reflected signal, the

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

• configurations with increasing control over their optical performance [1][2][3][4]. The strong local near-field enhancement by plasmonic nanoantennas is being harnessed for high sensitivity, high-resolution optical nanospectroscopy techniques [5], such as surface-enhanced or tip-enhanced Raman spectroscopy (SERS

• enhanced optical mode density can, for example, enhance the excitation and/or the emission rate of a quantum system that is positioned in this near-field region [28]. Both the enhanced local field and optical mode density are of great practical use for local spectroscopy with extremely high spatial

• 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

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• beam. The near field localized at the tip apex enhances the optical field in the tip–sample gap by several orders of magnitude and simultaneously directs the emitted photons from the gap into the far field for detection. With recent demonstrations of a spatial resolution even at the angstrom level [25

• dominant field component lays out-of-plane (parallel to the tip shaft). Figure 4b,c demonstrates that the tip apex can be easily excited, which is a precondition for producing a localized near field at the tip apex. Next, we approached the sample to the tip and recorded the topography (size: 250 × 250 nm2

• of Si at about 520 cm−1 with the equation: In c-Si with cubic diamond structure, ΔΘ has a value of 0°, whereas in a-Si films ΔΘ was experimentally determined to be in the range of 7.7° ≤ ΔΘ ≤ 10.5°. In our experiments we calculated ΔΘavg,n-f = 9.2° and ΔΘavg,conf = 8.3° based on the near-field and

Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

• Jingran Zhang,
• Tianqi Jia,
• Yongda Yan,
• Li Wang,
• Peng Miao,
• Yimin Han,
• Xinming Zhang,
• Guangfeng Shi,
• Yanquan Geng,
• Zhankun Weng,
• Daniel Laipple and
• Zuobin Wang

Beilstein J. Nanotechnol. 2019, 10, 2483–2496, doi:10.3762/bjnano.10.239

• chemical (CM) [5] and electromagnetic enhancement (EM) [6][7]. The CM enhancement is the main factor for charge transfer between the SERS substrate and probe molecule. The EM field enhancement is the main factor for localized surface plasmon resonance (LSPR) and significantly depends on the induced near

• -field intensity. The size, shape, and interparticle spacing of the nanoparticles or nanostructures influences the LSPR. A series of metals including Au, Cu and Ag are useful in ultra-trace biological or chemical sensing and have shown great potential to obtain surface enhancement. Thus, many different

Atomic force acoustic microscopy reveals the influence of substrate stiffness and topography on cell behavior

• Yan Liu,
• Li Li,
• Xing Chen,
• Ying Wang,
• Meng-Nan Liu,
• Jin Yan,
• Liang Cao,
• Lu Wang and
• Zuo-Bin Wang

Beilstein J. Nanotechnol. 2019, 10, 2329–2337, doi:10.3762/bjnano.10.223

• obtain quantitative information on undeveloped and developed SU-8 film surfaces. AFAM uses the near-field detection of acoustic signals to study surfaces and even buried structures [31][32]. For AFAM, a transducer generates ultrasound waves propagating into the sample to cause vibrations of the sample

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

• Alberto Boretti,
• Lorenzo Rosa,
• Jonathan Blackledge and
• Stefania Castelletto

Beilstein J. Nanotechnol. 2019, 10, 2128–2151, doi:10.3762/bjnano.10.207

• contribution in these NDs is due to nearby nitrogen impurities rather than surface states. Improved ND NV center electron spin properties were obtained in [48] by a room-temperature near-field etching method. This is based on application of a He–Cd ultraviolet laser (325 nm), which has a longer wavelength than

Experimental study of an evanescent-field biosensor based on 1D photonic bandgap structures

• Jad Sabek,
• Francisco Javier Díaz-Fernández,
• Luis Torrijos-Morán,
• Zeneida Díaz-Betancor,
• Ángel Maquieira,
• María-José Bañuls,
• Elena Pinilla-Cienfuegos and
• Jaime García-Rupérez

Beilstein J. Nanotechnol. 2019, 10, 967–974, doi:10.3762/bjnano.10.97

• of proteins. As the sensing in this type of structures is governed by the interaction between the evanescent field going into the cladding and the target analytes, scanning near-field optical microscopy has been used to characterize the profile of that evanescent field. The study confirms the strong

• the interaction with the target analytes in evanescent-wave-based sensors, specifically for the case of PBG sensing structures, and thus to increase the sensitivity of the sensors. The evanescent field of this type of sensing structures has been thoroughly characterized using scanning near-field

• optical microscopy (SNOM) in order to determine how the interaction will vary with the distance to the sensor surface. This near-field characterization has demonstrated the importance of having biorecognition layers being as thin as possible in order to reach optimal sensitivities. Taking this requirement

Nanoscale optical and structural characterisation of silk

• Meguya Ryu,
• Reo Honda,
• Adrian Cernescu,
• Arturas Vailionis,
• Armandas Balčytis,
• Jitraporn Vongsvivut,
• Jing-Liang Li,
• Denver P. Linklater,
• Elena P. Ivanova,
• Vygantas Mizeikis,
• Mark J. Tobin,
• Junko Morikawa and
• Saulius Juodkazis

Beilstein J. Nanotechnol. 2019, 10, 922–929, doi:10.3762/bjnano.10.93

• determination of optical properties that are related to the mass density and its gradients. It is important to measure n and κ from decreasingly smaller volumes and to compare with data obtained from the bulk samples. Here, we used a near-field scattering method to probe n and κ and to determine spectral

• diffractometer using a Cu Kα microfocus X-ray source with λ = 1.5418 Å (Figure 2a). IR spectral measurements The sub-diffraction scattering scanning near-field optical microscope (s-SNOM, neaspec GmbH) uses a metalized atomic force microscopy (AFM) tip. The tip maps the surface relief (topography) by its basic

• the near-field interaction between the tip and sample [15]. An asymmetric Michelson interferometer and a lock-in detection of the signal at higher harmonic of the tapping frequency (approximately 250 kHz) provides background-free nano-IR spectra and images with maximum resolution imposed by the AFM

Biomimetic synthesis of Ag-coated glasswing butterfly arrays as ultra-sensitive SERS substrates for efficient trace detection of pesticides

• Guochao Shi,
• Mingli Wang,
• Yanying Zhu,
• Yuhong Wang,
• Xiaoya Yan,
• Xin Sun,
• Haijun Xu and
• Wanli Ma

Beilstein J. Nanotechnol. 2019, 10, 578–588, doi:10.3762/bjnano.10.59

• . Simultaneously, suitable nanogaps between the adjacent nanostructures were generated in which high near-field enhancement could be achieved. As shown in the inset of Figure 2e, where the Nano Measurer 1.2 software was used, the average width of the nanofilm was approximately 170 ± 10 nm (the average width was

Electromagnetic analysis of the lasing thresholds of hybrid plasmon modes of a silver tube nanolaser with active core and active shell

• Denys M. Natarov,
• Trevor M. Benson and
• Alexander I. Nosich

Beilstein J. Nanotechnol. 2019, 10, 294–304, doi:10.3762/bjnano.10.28

• presents the |Hz| near-field portraits of several HLSP lasing modes, , with azimuthal indices m = 1, 3 and 10, of a thin-wall (h = 10 nm) silver nanotube laser; these modes are also marked on the trajectories to be presented in Figures 5 to 7. The features of the mode fields that explain our notations are

• larger), then modes lose their hybrid features and transform to the LSP modes (of the same m) of the solid circular metal wire of radius r = a + h and of the void of radius r = a in the metal host medium, respectively. This is visible in the near-field portraits of the modes with azimuthal indices m

Low cost tips for tip-enhanced Raman spectroscopy fabricated by two-step electrochemical etching of 125 µm diameter gold wires

• Antonino Foti,
• Francesco Barreca,
• Enza Fazio,
• Cristiano D’Andrea,
• Paolo Matteini,
• Onofrio Maria Maragò and
• Pietro Giuseppe Gucciardi

Beilstein J. Nanotechnol. 2018, 9, 2718–2729, doi:10.3762/bjnano.9.254

• on the applications of TERS can be found in [20][21][22][23][24][25]. TERS features unique advantages as compared with scanning electron microscopy (SEM), scanning near-field Raman microscopy (Raman-SNOM) [26] and far-field nanoscopy [27][28]: (i) it is a label-free technique, i.e., it does not

• near-field coupling. For our purposes, mapping the light emission from the tip is important for two reasons. Firstly, we have empirically verified that optimal tips for TERS are those that show some degree of light emission from their apex. Secondly, the process allows us to precisely focus the laser

• removed from the near-field region of the sample, just excluding the feedback loop of the STM system. Vibrational bands of all molecules agree with the literature [60][61][62][63]. We finally apply our tips to obtain TERS spectra from the N-terminal domain of the Escherichia coli protein HypF (HypF-N

Silencing the second harmonic generation from plasmonic nanodimers: A comprehensive discussion

• Jérémy Butet,
• Gabriel D. Bernasconi and
• Olivier J. F. Martin

Beilstein J. Nanotechnol. 2018, 9, 2674–2683, doi:10.3762/bjnano.9.250

• dependence, revealing distinct behaviors as the fundamental near-field distribution changes. The role of the antenna modes at the second harmonic wavelength in the enhancement of the SHG has also been addressed for symmetric and asymmetric antennas, showing that the SHG is strongly modified by a gap

• well-known and has been reported in various publications – it has been established, as a cornerstone of nonlinear plasmonics, that the nonlinear optical responses of plasmonic nanostructures is boosted by LSPRs [31][32]. Indeed, a strong near-field enhancement is associated with the collective

• this phenomenon, the near-field intensity enhancement is now discussed. The fundamental intensity enhancements for the gold dimers have been evaluated at the dimer extremities, respectively in the nanogap, and are shown in Figure 2 as a function of the fundamental wavelength, respectively in panels (a