A review on nanostructured silver as a basic ingredient in medicine: physicochemical parameters and characterization

• Gabriel M. Misirli,
• Kishore Sridharan and
• Shirley M. P. Abrantes

Beilstein J. Nanotechnol. 2021, 12, 440–461, doi:10.3762/bjnano.12.36

• equations. Following the discrete dipole approximation (DDA), it is possible to calculate the dipole polarized by the incident light and all the other dipoles in the nanoparticle matrix, in addition to predicting the behavior of their respective spectra. Figure 11 shows the extinction, absorption, and

Correlation of surface-enhanced Raman scattering (SERS) with the surface density of gold nanoparticles: evaluation of the critical number of SERS tags for a detectable signal

• Vincenzo Amendola

Beilstein J. Nanotechnol. 2019, 10, 1016–1023, doi:10.3762/bjnano.10.102

• suitability of plasmonic SERS labels for ultrasensitive analytical and biomedical applications is evident. Keywords: discrete dipole approximation (DDA); gold nanoparticles (AuNPs); nanotags; surface-enhanced Raman scattering (SERS); surface plasmon resonance (SPR); Introduction In surface-enhanced Raman

• 100 s. Numerical calculations The local field, Eloc, was calculated with the discrete dipole approximation (DDA) method using the software DDSCAT 7.1 and the related DDFIELD code [44][45][46]. A nanoaggregate of Au nanoparticles was created with same structure taken from a representative TEM picture

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

• describe the roughness of scattering objects include the finite element method (FEM) [29], the finite difference time domain (FDTD) method [30], the coupled wave method (CWM) [31], the discrete dipole approximation (DDA) [32][33], for which the meshing of the rough surface may be critical for computation

Tunable longitudinal modes in extended silver nanoparticle assemblies

• Serene S. Bayram,
• Klas Lindfors and
• Amy Szuchmacher Blum

Beilstein J. Nanotechnol. 2016, 7, 1219–1228, doi:10.3762/bjnano.7.113

• (Supporting Information File 1, Figure S6). To gain insight into the optical properties of the AgNPs aggregates, we carried out discrete-dipole approximation (DDA) simulations of random chains of silver spheres. Random chains of particles with different lengths were generated by attaching particles to the end

• were used in the simulations [44]. All simulations were performed with water as the surrounding medium. For water a constant refractive index of 1.33 was used. Absorption spectra for the particle aggregates were calculated using an in-house developed program implementing the discrete-dipole

• approximation (DDA) method [45]. A similar approach as the method used here has been earlier successfully used to model DNA-assembled nanospheres [46]. Extinction spectra of AgNPs modified by varying ratios of ligands: A) cysteamine, B) DTT and C) cysteine. Legend: r = number of ligand molecules/AgNP. Insets

Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation

• Guoke Wei,
• Jinliang Wang and
• Yu Chen

Beilstein J. Nanotechnol. 2015, 6, 686–696, doi:10.3762/bjnano.6.69

• The enhancement factor (EF) of surface-enhanced Raman scattering (SERS) from two-dimensional (2D) hexagonal silver nanorod (AgNR) arrays were investigated in terms of electromagnetic (EM) mechanism by using the discrete dipole approximation (DDA) method. The dependence of EF on several parameters, i.e

• nanoarrays and incident excitations will shine light on the optimal design of efficient SERS substrates and improved performance. Keywords: discrete dipole approximation (DDA); enhancement factor; near-field; silver nanorod array; surface-enhanced Raman scattering (SERS); Introduction Surface-enhanced

• used in experimental studies hindered the direct comparison. Here, we took a systematic approach to investigate the SERS enhancements of the two-dimensional (2D) AgNR arrays from the perspective of EM enhancement mechanism by using the discrete dipole approximation (DDA) method [19]. We expect that the

Optical near-fields & nearfield optics

• Alfred J. Meixner and
• Paul Leiderer

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

• “optical antenna”. Since the fabrication of suitable structures with electron beam or focused ion beam lithography is a tedious and time-consuming task, the experiments are more and more supported by modeling with numerical methods such as Finite Difference Time Domain (FDTD) and Discrete Dipole

• Approximation (DDA). For the modeling to be reliable, it is essential to quantitatively compare the results of simulations with experimental data. To this end, various schemes have been developed, like Scanning Near-field Optical Microscopy (SNOM) and Photoelectron Electron Microscopy (PEEM), in order to image

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

• object. Two main factors are complicating this task: Firstly, solving Maxwell´s equations for a system more complex than a simple geometric object requires a certain amount of simplification or a careful numerical treatment. Commonly used numerical simulation methods are, for example, discrete dipole

• approximation (DDA) or finite-difference in the time-domain (FDTD). Secondly, the outcome of these simulations has to be compared to a measurement of the field distribution. Since the field enhancement can be highly confined, direct probing of the field distribution is rather challenging. Experimental