All Outputs (118)

Helmholtz dark spatial optical solitons for a defocusing saturable nonlinearity
Presentation / Conference
defocusing saturable nonlinearity. Presented at European Optical Society Annual Meeting (EOSAM 2012), Aberdeen, Scotland, UK

We report on our latest developments in the field of Helmholtz soliton theory: the derivation of exact dark spatial optical solitons for a defocusing saturable nonlinearity. A raft of new physical predictions is made, and extensive analysis (via bot... Read More about Helmholtz dark spatial optical solitons for a defocusing saturable nonlinearity.

Nonparaxial refraction laws for spatial solitons at cubic-quintic material interfaces
Presentation / Conference
cubic-quintic material interfaces. Presented at National Photonics Conference, Photon12, University of Durham, UK

The behaviour of light at the interface between different materials essentially underpins the entire field of Optics. In nonlinear photonics, a building-block geometry comprises a spatial soliton incident on the planar boundary between two dissimila... Read More about Nonparaxial refraction laws for spatial solitons at cubic-quintic material interfaces.

Helmholtz spatial solitons and oblique propagation in coupled-waveguide arrays
Presentation / Conference
Christian, J., McCoy, E., McDonald, G., Sanchez-Curto, J., & Chamorro-Posada, P. Helmholtz spatial solitons and oblique propagation in coupled-waveguide arrays. Presented at National Photonics Conference, Photon12, University of Durham, UK

The interaction between light waves and layered host media is a fundamental class of problem in nonlinear photonics. For example, the interest may lie with studying the behaviour of a spatial optical soliton: (i) at the planar boundary between other... Read More about Helmholtz spatial solitons and oblique propagation in coupled-waveguide arrays.

Helmholtz dark spatial solitons in waveguides with defocusing saturable materials
Presentation / Conference
with defocusing saturable materials. Presented at National Photonics Conference, Photon12, University of Durham, UK

Angular configurations play a fundamental role in essentially all nonlinear photonic architectures: from beam multiplexing applications, to scattering at a single interface, to evolution inside patterned optical structures. Equations of the nonline... Read More about Helmholtz dark spatial solitons in waveguides with defocusing saturable materials.

Two-colour spatial optical solitons: new stability analyses for off-axis propagation
Presentation / Conference
new stability analyses for off-axis propagation. Presented at National Photonics Conference, Photon12, University of Durham, UK

Two-colour spatial optical solitons comprise a pair of stationary continuous-wave light beams at two well-separated temporal frequencies. The components overlap in the propagation plane and are coupled through system nonlinearity (e.g., the Kerr-typ... Read More about Two-colour spatial optical solitons: new stability analyses for off-axis propagation.

Instabilities and Helmholtz vector solitons in nonlinearly-coupled optical systems
Presentation / Conference
nonlinearly-coupled optical systems. Presented at Second Annual Student Conference on Complexity Science (SCCS 2012), University of Gloucestershire, UK

The propagation of, and interaction between, multiple waves is a fundamental problem in physical science. The interplay between linear and nonlinear processes – such as diffraction (wave spreading) and self-/cross-phase modulation (wave compressing)... Read More about Instabilities and Helmholtz vector solitons in nonlinearly-coupled optical systems.

Propagation properties of Helmholtz power-law nonlinear surface waves
Presentation / Conference
nonlinear surface waves. Presented at Second Annual Student Conference on Complexity Science (SCCS 2012), University Gloucestershire, UK

Optical surface waves are a fundamental class of excitation in inhomogeneous nonlinear photonic systems. This type of laser light satisfies a Helmholtz-type governing equation, and is subject to certain boundary conditions. It also has an asymmetri... Read More about Propagation properties of Helmholtz power-law nonlinear surface waves.

Nonparaxial refraction and giant Goos-Hänchen shifts at nonlinear optical interfaces
Presentation / Conference
at nonlinear optical interfaces. Presented at Second Annual Student Conference on Complexity Science (SCCS 2012), University of Gloucestershire

The scattering of spatial optical solitons (self-localizing beams of laser light) at the interface between two dissimilar materials is a problem of fundamental importance in nonlinear photonics. Theoretical analyses must take into account a highly c... Read More about Nonparaxial refraction and giant Goos-Hänchen shifts at nonlinear optical interfaces.

Spatial soliton refraction at cubic-quintic material interfaces
Presentation / Conference
McCoy, E., Christian, J., & McDonald, G. Spatial soliton refraction at cubic-quintic material interfaces. Poster presented at Salford Postgraduate Annual Research Conference (SPARC 11), University of Salford, Greater Manchester, UK

In their most general form, wave–interface problems are inherently angular in nature. For instance, the interaction between light waves and material boundaries essentially defines the entire field of optics [1]. The seminal works of Aceves et al. [2,... Read More about Spatial soliton refraction at cubic-quintic material interfaces.

From Turing instability to fractals
Presentation / Conference
Huang, J., Christian, J., McDonald, G., Jahanpanah, J., & Chamorro-Posada, P. From Turing instability to fractals. Presented at Nonlinear Photonics Topical Meeting, Quebec City, Canada

Complexity focuses on commonality across subject areas and forms a natural platform for multidisciplinary activities. Typical generic signatures of complexity include: (i) spontaneous occurrence of simple patterns (e.g. stripes, squares, hexagons) em... Read More about From Turing instability to fractals.

Helmholtz solitons: a new angle in nonlinear optics
Presentation / Conference
Christian, J., McDonald, G., Chamorro-Posada, P., & Sanchez-Curto, J. Helmholtz solitons: a new angle in nonlinear optics. Poster presented at Nonlinear Photonics Topical Meeting, Quebec City, Canada

We rigorously show that nonparaxial optical beams are not necessarily ultranarrow [1-3]. While existing paraxial models constrain considerations of broad beams to vanishingly-small propagation angles relative to the longitudinal (i.e. z) direction,... Read More about Helmholtz solitons: a new angle in nonlinear optics.

Helmholtz solitons: a new angle in nonlinear science
Presentation / Conference
Chamorro-Posada, P., McDonald, G., Sanchez-Curto, J., & Christian, J. Helmholtz solitons: a new angle in nonlinear science. Presented at Nonlinear Evolution Equations and Dynamical Systems (NEEDS), L’Ametlla de Mar, Spain

The ubiquitous nonlinear SchrÄodinger (NLS) equation models soliton propagation in many di®erent scenarios. In a nutshell, the NLS equation describes the slow modulation of the envelope of a linear wave when propagating in a weakly nonlinear medium.... Read More about Helmholtz solitons: a new angle in nonlinear science.

Peristaltic flow of non-Newtonian, compressible fluid with non-zero boundary slip
Presentation / Conference
Tsiklauri, D., Christian, J., & McDonald, G. Peristaltic flow of non-Newtonian, compressible fluid with non-zero boundary slip. Poster presented at Materials Congress: Institute of Materials, Minerals, and Mining (IoM3), London, UK

In Tsiklauri & Beresnev, Phys Rev E 64, 036303 (2001), we investigated new phenomena brought about into the classic peristaltic mechanism by the inclusion of non-Newtonian effects based on the model of a Maxwell fluid. In Tsiklauri, J Acoust Soc Am 1... Read More about Peristaltic flow of non-Newtonian, compressible fluid with non-zero boundary slip.

Peristaltic wave propagation in compressible Maxwell fluids with boundary slip
Presentation / Conference
Christian, J., Tsiklauri, D., & McDonald, G. Peristaltic wave propagation in compressible Maxwell fluids with boundary slip. Poster presented at Condensed Matter and Materials Physics Conference, University of Exeter, UK

Boundary slip has recently been observed by Craig et al. [Phys Rev Lett 87, 054504 (2001)]. Complementing this work, Tsiklauri [J Acoust Soc Am 112, 843 (2002)] incorporated non-zero boundary slip into a theoretical model of fluid-saturated porous me... Read More about Peristaltic wave propagation in compressible Maxwell fluids with boundary slip.

Helmholtz solitons in non-Kerr media
Presentation / Conference
Christian, J., McDonald, G., & Chamorro-Posada, P. Helmholtz solitons in non-Kerr media. Poster presented at 25th European Quantum Electronics Conference (CLEO Europe/EQEC), Munich, Germany

Spatial optical soliton propagation in a planar waveguide is often modelled by a Non-Linear Schrödinger (NLS) type equation. Such systems are paraxial in nature, and cannot describe accurately off-axis propagation at nontrivial angles. The NLS equat... Read More about Helmholtz solitons in non-Kerr media.

Helmholtz-Manakov solitons
Presentation / Conference
Christian, J., McDonald, G., & Chamorro-Posada, P. Helmholtz-Manakov solitons. Presented at 25th European Quantum Electronics Conference (CLEO Europe/EQEC), Munich, Germany

The propagation of a spatial vector soliton beam in a Kerr planar waveguide is typically described by the Manakov equation [1]. However, the assumption of beam paraxiality breaks the rotational symmetry of the wave propagation problem. Manakov-based... Read More about Helmholtz-Manakov solitons.

Fresnel diffraction from polygonal apertures
Presentation / Conference
Huang, J., Christian, J., & McDonald, G. Fresnel diffraction from polygonal apertures. Poster presented at 25th European Quantum Electronics Conference (CLEO Europe/EQEC), Munich, Germany

We present, for the first time, two complementary analytical techniques for calculating the Fresnel diffraction patterns from a polygonal aperture illuminated by a plane wave. These frameworks are exact, in that they do not involve any further approx... Read More about Fresnel diffraction from polygonal apertures.

Nonlinear wave phenomena at optical boundaries: spatial soliton refraction
Presentation / Conference
McCoy, E., Christian, J., & McDonald, G. Nonlinear wave phenomena at optical boundaries: spatial soliton refraction. Presented at 2nd CSE Doctoral School Postgraduate Research Conference, University of Salford, Greater Manchester, UK

The behaviour of light at the interface between different materials underpins the entire field of Optics. Arguably the simplest manifestation of this phenomenon – the reflection and refraction characteristics of (infinitely-wide) plane waves at the... Read More about Nonlinear wave phenomena at optical boundaries: spatial soliton refraction.