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All Outputs (169)

Dark spatial soliton break-up in the transverse plane (1993)
Journal Article
Mcdonald, G., Syed, K., & Firth, W. (1993). Dark spatial soliton break-up in the transverse plane. Optics Communications, 95(4-6), 281-288. https://doi.org/10.1016/0030-4018%2893%2990679-Y

We report on numerical simulations investigating the instabilities which arise when dark soliton solutions of the two-dimensional (2D) nonlinear Schrödinger equation are allowed to propagate in a 3D self-defocussing medium. Firstly, propagation of fu... Read More about Dark spatial soliton break-up in the transverse plane.

Spatial grid symmetries and reduced models in the simulation of beam counterpropagation in a nonlinear medium (1993)
Journal Article
Mcdonald, G., & Firth, W. (1993). Spatial grid symmetries and reduced models in the simulation of beam counterpropagation in a nonlinear medium. Journal of Modern Optics, 40(1), 23-32. https://doi.org/10.1080/09500349314550041

In the context of the nonlinear interaction of counterpropagating light beams, we demonstrate the unrealistic symmetries that arise in the simulation of spontaneous pattern formation when using square computational grids. We have formulated a general... Read More about Spatial grid symmetries and reduced models in the simulation of beam counterpropagation in a nonlinear medium.

Optical vortices in beam propagation through a self-defocussing medium (1992)
Journal Article
Mcdonald, G., Syed, K., & Firth, W. (1992). Optical vortices in beam propagation through a self-defocussing medium. Optics Communications, 94(5), 469-476. https://doi.org/10.1016/0030-4018%2892%2990589-J

We present numerical simulations and analysis of optical vortex propagation in a 3D self-defocussing medium. On plane wave background initial conditions composed of points and lines of phase discontinuity are shown, in some cases, to evolve towards a... Read More about Optical vortices in beam propagation through a self-defocussing medium.

Hexagon patterns in optical bistability (1992)
Journal Article
Firth, W., Scroggie, A., McDonald, G., & Lugiato, L. (1992). Hexagon patterns in optical bistability. Physical Review A, 46(7), R3609-R3612. https://doi.org/10.1103/PhysRevA.46.R3609

The mean-field model of optical bistability in a ring cavity is extended to include diffraction in two transverse dimensions. Nonlinear analysis in the neighborhood of the instability of the homogeneous solution indicates the formation of stable hexa... Read More about Hexagon patterns in optical bistability.

Spatial solitary-wave optical memory (1990)
Journal Article
Mcdonald, G., & Firth, W. (1990). Spatial solitary-wave optical memory. Journal of the Optical Society of America B, 7(7), 1328-1335. https://doi.org/10.1364/JOSAB.7.001328

We consider some features of spatial solitary-wave switching in a unidirectional ring cavity that is partially filled with a fast and saturably self-focusing nonlinear medium. Large (part-beam switched) solitary arrays are considered. It is found tha... Read More about Spatial solitary-wave optical memory.

All-optical switching in a nonlinear resonator (1990)
Journal Article
Mcdonald, G., & Firth, W. (1990). All-optical switching in a nonlinear resonator. Journal of Modern Optics, 37(4), 613-626. https://doi.org/10.1080/09500349014550701

In this paper we consider some features of all-optical switching in a unidirectional ring cavity which is partially filled with a fast and saturably nonlinear medium. A comparative study of cross-talk for both signs of nonlinearity, in a two pixel (w... Read More about All-optical switching in a nonlinear resonator.

Multi-Turing instabilities and spatial patterns in discrete systems : simplicity and complexity, cavities and counterpropagation
Presentation / Conference
Bostock, C., Christian, J., Leite, A., McDonald, G., & Huang, J. Multi-Turing instabilities and spatial patterns in discrete systems : simplicity and complexity, cavities and counterpropagation. Poster presented at 6th European Optical Society Annual Meeting (EOSAM 2016), Berlin Adlershof, Germany

The spontaneous pattern-forming properties of three discrete nonlinear optical
systems are investigated, including the proposal of two new physical contexts for
coupled-waveguide geometries. Linear analyses predict Turing threshold instability
spe... Read More about Multi-Turing instabilities and spatial patterns in discrete systems : simplicity and complexity, cavities and counterpropagation.

Vector waves with spatiotemporal dispersion and \chi(3) nonlinearity : transformations and relativity, solitons and stability
Presentation / Conference
Carter, L., Christian, J., & McDonald, G. Vector waves with spatiotemporal dispersion and \chi(3) nonlinearity : transformations and relativity, solitons and stability. Poster presented at 6th European Optical Society Annual Meeting (EOSAM 2016), Berlin Adlershof, Germany

A vector model, fully-second-order in both space and time, is proposed for coupled
electromagnetic modes in nonlinear waveguides. Our formalism has strong overlaps
with the special relativity. Exact two-component solitons are derived, asymptotic
a... Read More about Vector waves with spatiotemporal dispersion and \chi(3) nonlinearity : transformations and relativity, solitons and stability.

Dissipative solitons of a spatiotemporal Ginzburg-Landau equation
Presentation / Conference
Cooper, A., Christian, J., Bresnahan, D., McDonald, G., & Chamorro-Posada, P. Dissipative solitons of a spatiotemporal Ginzburg-Landau equation. Presented at Quantum Electronics and Photonics Conference (Photon14/QEP-21), Imperial College London, UK

Diffraction of fractal light by simple apertures
Presentation / Conference
Mylova, M., Christian, J., & McDonald, G. Diffraction of fractal light by simple apertures. Presented at Quantum Electronics and Photonics Conference (Photon14/QEP-21), Imperial College London, UK

We propose and investigate, for the first time to our knowledge, an entirely new
regime in wave physics  the diffraction of fractal waves from simple apertures. A
selection of new analyses and physical predictions will be given for experimental
g... Read More about Diffraction of fractal light by simple apertures.

Spatiotemporal vector solitons in nonlinear optical systems with \chi(3) susceptibility
Presentation / Conference
Ashley, J., Christian, J., McDonald, G., & Chamorro-Posada, P. Spatiotemporal vector solitons in nonlinear optical systems with \chi(3) susceptibility. Presented at 5th European Optical Society Annual Meeting, Berlin, Germany

A new model is proposed for describing coupled optical waves propagating in a system with linear dispersion (both group-velocity and spatial contributions) \chi(3 nonlinear susceptibility. The modulational instability problem is solved in full, and... Read More about Spatiotemporal vector solitons in nonlinear optical systems with \chi(3) susceptibility.

Multi-turing instabilities in Fabry-Perot resonators and discrete microcavities
Presentation / Conference
Bostock, C., Christian, J., McDonald, G., Leite, A., & Huang, J. Multi-turing instabilities in Fabry-Perot resonators and discrete microcavities. Presented at 5th European Optical Society Annual Meeting, Berlin, Germany

We report on research concerning spontaneous spatial fractal pattern formation in
passive nonlinear optical cavities (both ring-resonator and Fabry-Pérot geometries).
A new model for light propagation inside discrete coupled cavities is proposed... Read More about Multi-turing instabilities in Fabry-Perot resonators and discrete microcavities.

Diffraction of fractal optical fields by simple apertures
Presentation / Conference
Christian, J., Mylova, M., & McDonald, G. Diffraction of fractal optical fields by simple apertures. Presented at 5th European Optical Society Annual Meeting, Berlin, Germany

We propose and investigate, for the first time to our knowledge, an entirely new
regime in wave physics  the diffraction of fractal waves from simple apertures. A
selection of new analyses and physical predictions will be given for experimental... Read More about Diffraction of fractal optical fields by simple apertures.

Unstable cavity lasers - from kaleidoscopes to snowflakes
Presentation / Conference
Christian, J., Begleris, I., McDonald, G., & Huang, J. Unstable cavity lasers - from kaleidoscopes to snowflakes. Presented at 5th European Optical Society Annual Meeting (EOSAM 2014), Berlin, Germany

The snowflake laser is proposed  a new class of unstable resonator whose
feedback mirror has the shape of the von Koch snowflake. Theoretical analysis is
undertaken with two-dimensional virtual source theory, and predictions of novel mode
patt... Read More about Unstable cavity lasers - from kaleidoscopes to snowflakes.

Ultra-broadband frequency generation in a cavity confined Raman medium
Thesis
Rose, C. Ultra-broadband frequency generation in a cavity confined Raman medium. (Thesis). University of Salford

Throughout the past few decades, science has progressed towards the ability to probe many extremely fast processes and a large amount of research has been aimed at the area of few-femtosecond pulse generation. This thesis describes the generation of... Read More about Ultra-broadband frequency generation in a cavity confined Raman medium.

The spatiotemporal wave equation with a dual power-law nonlinearity
Presentation / Conference
Cowey, R., Christian, J., & McDonald, G. The spatiotemporal wave equation with a dual power-law nonlinearity. Poster presented at Salford Postgraduate Annual Research Conference (SPARC 2013), University of Salford

Solitons and soliton-like emergent phenomena appear ubiquitously throughout nonlinear science. These waves are truly fundamental entities, transcending the physical details of a system and resulting whenever linear dispersion (which tends to broaden... Read More about The spatiotemporal wave equation with a dual power-law nonlinearity.