Dark gap solitons in bichromatic optical superlattices under cubic-quintic nonlinearities.

We demonstrate the existence of two types of dark gap solitary waves-the dark gap solitons and the dark gap soliton clusters-in Bose-Einstein condensates trapped in a bichromatic optical superlattice with cubic-quintic nonlinearities. The background of these dark soliton families is different from the one in a common monochromatic linear lattice; namely, the background in our model is composed of two types of Gaussian-like pulses, whereas in the monochromatic linear lattice, it is composed of only one type of Gaussian-like pulses. Such a special background of dark soliton families is convenient for the manipulation of solitons by the parameters of bichromatic and chemical potentials.

-symmetric photonic lattices with type-II Dirac cones.

The type-II Dirac cone is a special feature of the band structure, whose Fermi level is represented by a pair of crossing lines. It has been demonstrated that such a structure is useful for investigating topological edge solitons and, more specifically, for mimicking the Klein tunneling. However, it is still not clear what the interplay between type-II Dirac cones and the non-Hermiticity mechanism will result in.

Mode conversion of various solitons in parabolic and cross-phase potential wells.

We numerically establish the controllable conversion between Laguerre-Gaussian and Hermite-Gaussian solitons in nonlinear media featuring parabolic and cross-phase potential wells. The parabolic potential maintains the stability of Laguerre-Gaussian and Hermite-Gaussian beams, while the actual conversion between the two modes is facilitated by the cross-phase potential, which induces an additional phase shift. By flexibly engineering the range of the cross-phase potential well, various higher-mode solitons can be generated at desired distances.

Surface gap solitons in the Schrödinger equation with quintic nonlinearity and a lattice potential.

We demonstrate the existence of surface gap solitons, a special type of asymmetric solitons, in the one-dimensional nonlinear Schrödinger equation with quintic nonlinearity and a periodic linear potential. The nonlinearity is suddenly switched in a step-like fashion in the middle of the transverse spatial region, while the periodic linear potential is chosen in the form of a simple sin lattice. The asymmetric nonlinearities in this work can be realized by the Feshbach resonance in Bose-Einstein condensates or by the photorefractive effect in optics.

Mapping the Direction of Nucleocytoplasmic Transport of Glucocorticoid Receptor (GR) in Live Cells Using Two-Foci Cross-Correlation in Massively Parallel Fluorescence Correlation Spectroscopy (mpFCS).

Nucleocytoplasmic transport of transcription factors is vital for normal cellular function, and its breakdown is a major contributing factor in many diseases. The glucocorticoid receptor (GR) is an evolutionarily conserved, ligand-dependent transcription factor that regulates homeostasis and response to stress and is an important target for therapeutics in inflammation and cancer. In unstimulated cells, the GR resides in the cytoplasm bound to other molecules in a large multiprotein complex.

Interdimensional radial discrete diffraction in Mathieu photonic lattices.

We demonstrate transitional dimensionality of discrete diffraction in radial-elliptical photonic lattices. Varying the order, characteristic structure size, and ellipticity of the Mathieu beams used for the photonic lattices generation, we control the shape of discrete diffraction distribution over the combination of the radial direction with the circular, elliptic, or hyperbolic. We also investigate the transition from one-dimensional to two-dimensional discrete diffraction by varying the input probe beam position.

Spiraling Laguerre-Gaussian solitons and arrays in parabolic potential wells.

Controllable trajectories of beams are one of the main themes in optical science. Here, we investigate the propagation dynamics of Laguerre-Gaussian (LG) solitons in parabolic potential wells and introduce off-axis and chirp parameters (which represent the displacement and the initial angle of beams) to make solitons sinusoidally oscillate in the x and y directions and undergo elliptically or circularly spiraling trajectories during propagation. Additionally, LG solitons with different orders and powers can be combined into soliton arrays of various shapes, depending on the off-axis parameter.

Vector valley Hall edge solitons in distorted type-II Dirac photonic lattices.

Topological edge states have recently garnered a lot of attention across various fields of physics. The topological edge soliton is a hybrid edge state that is both topologically protected and immune to defects or disorders, and a localized bound state that is diffraction-free, owing to the self-balance of diffraction by nonlinearity. Topological edge solitons hold great potential for on-chip optical functional device fabrication.

Triangular bright solitons in nonlinear optics and Bose-Einstein condensates.

We demonstrate what we believe to be novel triangular bright solitons that can be supported by the nonlinear Schrödinger equation with inhomogeneous Kerr-like nonlinearity and external harmonic potential, which can be realized in nonlinear optics and Bose-Einstein condensates. The profiles of these solitons are quite different from the common Gaussian or sech envelope beams, as their tops and bottoms are similar to the triangle and inverted triangle functions, respectively. The self-defocusing nonlinearity gives rise to the triangle-up solitons, while the self-focusing nonlinearity supports the triangle-down solitons.

Soliton transformation between different potential wells.

This paper presents a novel, to the best of our knowledge, method for realizing soliton transformation between different potential wells by gradually manipulating their depths in the propagation direction. The only requirements for such a transformation are that the gradient of the manipulated depth is smooth enough and the solitons in different potential wells are both in the regions of stability. The comparison of transformed solitons with the iterative ones obtained by the accelerated imaginary-time evolution method proves that our method is efficient and reliable.

Vortex chaoticons in thermal nonlocal nonlinear media.

This paper numerically investigates the propagation of Laguerre-Gaussian vortex beams launched in nonlocal nonlinear media, such as lead glass. Our results show that the propagation properties depend on the selection of beam parameters m and p, which represent the azimuthal and radial mode numbers. When p=0, these profiles can be stable solitons for m≤2, or break up and then form a set of single-hump profiles for m≥3, which are unbounded states with scattered remnants of the energy.

Controllable propagation paths of gap solitons.

This paper numerically investigates the evolution of solitons in an optical lattice with gradual longitudinal manipulation. We find that the stationary solutions (with added noise to the amplitude) keep their width, profile, and intensity very well, although the propagation path is continuously changing during the modulated propagation. Discontinuities in the modulation functions cause the scattering of the beam that may end the stable propagation.

Experimental demonstration of optical Bloch oscillation in electromagnetically induced photonic lattices.

The optical Bloch oscillation (OBO) is an optical-quantum analogy effect that is significant for light field manipulations, such as light beam localization, oscillation and tunneling. As an intra-band oscillation, OBO was important for optical investigations in photonic lattices and atomic vapors over an extended period of time. However, OBO in reconfigurable platforms is still an open topic, even though tunability is highly desired in developing modern photonic techniques.

Solitions in magneto-optic waveguides with anti-cubic nonlinearity.

Optical soliton solutions are recovered for magneto-optic waveguides that maintains anti-cubic form of nonlinear refractive index. The analytical scheme is Jacobi's elliptic function approach. Once the solutions to the governing model are obtained in terms of Jacobi's elliptic functions, the limiting value to it's modulus of ellipticity reveals the complete spectrum of soliton solutions.

Computational investigation of cobalt and copper bis (oxothiolene) complexes as an alternative for olefin purification.

Considering that olefins present a large volume feedstock, it is reasonable to expect that their purification is industrially critical. After the discovery of the nickel bis (dithiolene) complex Ni(SC(CF)) that exhibits electro-catalytic activity with olefins but tends to decompose by a competitive reaction route, related complexes have been explored experimentally and theoretically. In this paper, a computational examination is performed on differently charged cobalt and copper bis (oxothiolene) complexes [M (OSC(CN))] to test their potential applicability as the catalysts for olefin purification, using the simplest olefin, ethylene.

Parity-time symmetry light bullets in a cold Rydberg atomic gas.

A scheme is proposed to generate stable light bullets (LBs) in a cold Rydberg atomic system with a parity-time (PT) symmetric potential, by utilizing electromagnetically induced transparency (EIT). Using an incoherent population pumping between two low-lying levels and spatial modulations of control and auxiliary laser fields, we obtain a two-dimensional (2D) periodic optical potential with PT symmetry. Based on PT symmetry potential and the long-range Rydberg-Rydberg atomic interaction, the system may support slow LBs with low light intensity.

Cubic-quartic bright optical solitons with improved Adomian decomposition method.

This paper numerically retrieves cubic-quartic solitons having power law of nonlinearity refractive index. An improvement of the Adomian decomposition scheme is the adopted algorithm of this work. The results are displayed along with the established error analysis.

Asymmetric conical diffraction in dislocated edge-centered square lattices: erratum.

Equations (1) and (2) in [Opt. Express27, 6300 (2019)10.1364/OE.

Asymmetric conical diffraction in dislocated edge-centered square lattices.

We investigate linear and nonlinear evolution dynamics of light beams propagating along a dislocated edge-centered square lattice. The band structure and Brillouin zones of this novel lattice are analyzed analytically and numerically. Asymmetric Dirac cones as well as the corresponding Bloch modes of the lattice are obtained.

Controllable optical rogue waves via nonlinearity management.

Using a similarity transformation, we obtain analytical solutions to a class of nonlinear Schrödinger (NLS) equations with variable coefficients in inhomogeneous Kerr media, which are related to the optical rogue waves of the standard NLS equation. We discuss the dynamics of such optical rogue waves via nonlinearity management, i.e.

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

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Optical Bloch oscillation and Zener tunneling in the fractional Schrödinger equation.

We demonstrate optical Bloch oscillation (OBO) and optical Zener tunneling (OZT) in the fractional Schrödinger equation (FSE) with periodic and linear potentials, numerically and theoretically. We investigate in parallel the regular Schrödinger equation and the FSE, by adjusting the Lévy index, and expound the differences between the two. We find that the spreading of the OBO decreases in the fractional case, due to the diminishing band width.

Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study.

Engineering of materials at the atomic level is one of the most important aims of nanotechnology. The unprecedented ability of scanning probe microscopy to address individual atoms opened up the possibilities for nanomanipulation and nanolitography of surfaces and later on of two-dimensional materials. While the state-of-the-art scanning probe lithographic methods include, primarily, adsorption, desorption and repositioning of adatoms and molecules on substrates or tailoring nanoribbons by etching of trenches, the precise modification of the intrinsic atomic structure of materials is yet to be advanced.

Insight into the Interactions of Amyloid β-Sheets with Graphene Flakes: Scrutinizing the Role of Aromatic Residues in Amyloids that Interact with Graphene.

The interaction of amyloid β-sheet segments with graphene-flake models is investigated by using DFT calculations. The structure of β-sheets of selected amyloid segments is based on crystal structures obtained from the Protein Data Bank. Our study, based on DFT calculations for model systems, indicates that the interaction in amyloid-graphene aggregates can be stronger than the interaction in the respective amyloid-amyloid aggregates.

Tunable invisibility cloaking by using isolated graphene-coated nanowires and dimers.

We investigate, both theoretically and numerically, a graphene-coated nano-cylinder illuminated by a plane electromagnetic wave in the far-infrared range of frequencies. We have derived an analytical formula that enables fast evaluation of the spectral window with a substantial reduction in scattering efficiency for a sufficiently thin cylinder. This polarization-dependent effect leads to tunable resonant invisibility that can be achieved via modification of graphene chemical potential monitored by the gate voltage.