Dr James Christian's Outputs (149)

Helmholtz surface wave propagation along nonlinear interfaces
Presentation / Conference
McCoy, E., Christian, J., & McDonald, G. Helmholtz surface wave propagation along nonlinear interfaces. Poster presented at Salford Postgraduate Annual Research Conference (SPARC 2013), University of Salford

When two dissimilar nonlinear photonic materials are placed together, the boundary between them forms an optical interface. A light beam (typically from a laser source) may then travel along the boundary as a surface wave, remaining trapped within t... Read More about Helmholtz surface wave propagation along nonlinear interfaces.

Giant Goos-Hänchen shifts and soliton refraction in systems with χ(5) susceptibility
Presentation / Conference
McCoy, E., Christian, J., & McDonald, G. Giant Goos-Hänchen shifts and soliton refraction in systems with χ(5) susceptibility. Presented at Salford Postgraduate Annual Research Conference (SPARC 2013), University of Salford

A full understanding of how a spatial solitons (a unique type of nonlinear light beam) behave when the encounter the boundary between two dissimilar media is still some way off. On the one hand, light-interface interactions underpin essentially all... Read More about Giant Goos-Hänchen shifts and soliton refraction in systems with χ(5) susceptibility.

Vector spatial solitons beyond the slowly-varying envelope approximation
Presentation / Conference
Bostock, C., Christian, J., & McDonald, G. Vector spatial solitons beyond the slowly-varying envelope approximation. Poster presented at Salford Postgraduate Annual Research Conference (SPARC 2013), University of Salford

The simultaneous propagation of two spatially-overlapping and differently-coloured laser beams (e.g., at infra-red and green wavelengths) in photonic waveguides has attracted much attention since the early 1990s [Shalaby & Barthelemy, IEEE J. Quantum... Read More about Vector spatial solitons beyond the slowly-varying envelope approximation.

Spontaneous spatial fractal light patterns in simple nonlinear cavities
Presentation / Conference
Bostock, C., Christian, J., & McDonald, G. Spontaneous spatial fractal light patterns in simple nonlinear cavities. Presented at Salford Postgraduate Annual Research Conference (SPARC 2013), University of Salford

Nature furnishes us with a wide variety of patterns that, fundamentally, tend to fall into one of two categories: simple (characterized by a dominant scale-length or “size”) or fractal (containing comparable levels of detail spanning decimal orders o... Read More about Spontaneous spatial fractal light patterns in simple nonlinear cavities.

Arbitrary-angle interaction of spatial solitons with layered photonic structures
Presentation / Conference
layered photonic structures. Presented at Salford Postgraduate Annual Research Conference (SPARC 2012), University of Salford, Greater Manchester, UK

The behaviour of light at the interface between different adjoining materials underpins the entire field of Optics. In nonlinear photonics, a fundamental geometry comprises a spatial soliton incident on the planar boundary between two dissimilar Ker... Read More about Arbitrary-angle interaction of spatial solitons with layered photonic structures.

Stability of two-colour spatial solitons in Helmholtz vector beam models
Presentation / Conference
in Helmholtz vector beam models. Presented at Salford Postgraduate Annual Research Conference (SPARC 2012), University of Salford, Greater Manchester, UK

This presentation will cover a few very basic aspects of our latest research into how laser beams behave when they travel through some types of materials. In particular, we are interested in the properties of overlapping light beams with different c... Read More about Stability of two-colour spatial solitons in Helmholtz vector beam models.

Spontaneous spatial fractal patterns in simple linear and nonlinear optical cavities
Presentation / Conference
linear and nonlinear optical cavities. Presented at European Optical Society Annual Meeting (EOSAM 2012), Aberdeen, Scotland, UK

We present an overview of our research on the fractal-generating properties of two distinct optical cavities: fractal eigenmodes of linear systems with inherent magnification, and spontaneous spatial fractals in nonlinear systems. Our latest research... Read More about Spontaneous spatial fractal patterns in simple linear and nonlinear optical cavities.

Nonparaxial refraction laws in optics: from non-Kerr interfaces to waveguide arrays
Presentation / Conference
from non-Kerr interfaces to waveguide arrays. Presented at European Optical Society Annual Meeting (EOSAM 2012), Aberdeen, Scotland, UK

Angular effects play a central role in essentially all non-trivial optical configurations, and can be well-described within a Helmholtz-type nonparaxial framework. We report recent results modelling spatial solitons interacting with cubic-quintic mat... Read More about Nonparaxial refraction laws in optics: from non-Kerr interfaces to waveguide arrays.

Spatial dispersion and spatiotemporal solitons in cubic-quintic optical waveguides
Presentation / Conference
in cubic-quintic optical waveguides. Presented at European Optical Society Annual Meeting (EOSAM 2012), Aberdeen, Scotland, UK

We report on fresh developments in the field of spatiotemporal optical solitons. A host of new analytical and numerical predictions for light pulses in nonlinear waveguides will be detailed, which have a simple physical interpretation. Tantalizing c... Read More about Spatial dispersion and spatiotemporal solitons in cubic-quintic optical waveguides.

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.