All Outputs (16)

Slepian eigenvalues as tunnelling rates (2022)
Journal Article
Creagh, S. C., & Gradoni, G. (2023). Slepian eigenvalues as tunnelling rates. Annals of Physics, 449, Article 169204. https://doi.org/10.1016/j.aop.2022.169204

We calculate the eigenvalues of an integral operator associated with Prolate Spheroidal Wave Functions (or Slepian functions) by interpreting them as tunnelling probabilities in an analogous quantum problem. Doing so allows us to extend a well-known... Read More about Slepian eigenvalues as tunnelling rates.

Tunnelling around bends—Wave scattering in curved shell structures (2020)
Journal Article
Mohammed, N. M., Creagh, S. C., & Tanner, G. (2021). Tunnelling around bends—Wave scattering in curved shell structures. Wave Motion, 101, Article 102697. https://doi.org/10.1016/j.wavemoti.2020.102697

A ray dynamics describing wave transport on curved and smooth thin shells can be obtained from the underlying wave equations via the Eikonal approximation. We analyse mid-frequency effects near the ring frequency for curved plates consisting of a cyl... Read More about Tunnelling around bends—Wave scattering in curved shell structures.

Nearfield acoustical holography – a Wigner function approach (2020)
Journal Article
Ramapriya, D. M., Gradoni, G., Creagh, S. C., Tanner, G., Moers, E., & Lopéz Arteaga, I. (2020). Nearfield acoustical holography – a Wigner function approach. Journal of Sound and Vibration, 486, Article 115593. https://doi.org/10.1016/j.jsv.2020.115593

We propose to use Wigner transformation methods as a tool for propagating measured acoustic signals from and towards a source region. We demonstrate the usefulness of the approach both for source reconstruction purposes and as a stable numerical simu... Read More about Nearfield acoustical holography – a Wigner function approach.

Modeling propagation in large deformed step-index fibers using a finite operator method (2019)
Journal Article
Kumar, D. S., Creagh, S. C., Sujecki, S., & Benson, T. M. (2019). Modeling propagation in large deformed step-index fibers using a finite operator method. Journal of the Optical Society of America B, 36(5), 1208-1221. https://doi.org/10.1364/josab.36.001208

© 2019 Optical Society of America. A finite operator model is applied to the propagation of light in deformed step-index fibers. The distribution of the light captured by the fiber from an arbitrary initial excitation is illustrated in the phase spac... Read More about Modeling propagation in large deformed step-index fibers using a finite operator method.

Elastodynamics on graphs: wave propagation on networks of plates (2018)
Journal Article
Brewer, C., Creagh, S. C., & Tanner, G. (2018). Elastodynamics on graphs: wave propagation on networks of plates. Journal of Physics A: Mathematical and Theoretical, 51(44), Article 445101. https://doi.org/10.1088/1751-8121/aae1d2

We consider the wave dynamics on networks of plates coupled along 1D joints. This set-up can be mapped onto an extension of wave graph systems studied in, for example, quantum graph theory. In the elastic case, different mode-types (flexural, longitu... Read More about Elastodynamics on graphs: wave propagation on networks of plates.

Modelling chaos in asymmetric optical fibres (2017)
Presentation / Conference Contribution
Kumar, D. S., Creagh, S., Sujecki, S., & Benson, T. M. (2017). Modelling chaos in asymmetric optical fibres. In 2017 19th International Conference on Transparent Optical Networks (ICTON) (1-5). https://doi.org/10.1109/ICTON.2017.8024908

A ray dynamical approach is developed for the study of large-core asymmetric step index fibres (SIF), especially those made from chalcogenide glasses (ChGs) which can exhibit very high refractive index, large numerical aperture, and which are transpa... Read More about Modelling chaos in asymmetric optical fibres.

Propagating wave correlations in complex systems (2016)
Journal Article
Creagh, S. C., Gradoni, G., Hartmann, T., & Tanner, G. (2016). Propagating wave correlations in complex systems. Journal of Physics A: Mathematical and Theoretical, 50(4), Article 45101. https://doi.org/10.1088/1751-8121/50/4/045101

We describe a novel approach for computing wave correlation functions inside finite spatial domains driven by complex and statistical sources. By exploiting semiclassical approximations, we provide explicit algorithms to calculate the local mean of t... Read More about Propagating wave correlations in complex systems.

Parity-time symmetric chain resonators (2016)
Presentation / Conference Contribution
Phang, S., Vukovic, A., Creagh, S., Gradoni, G., Sewell, P., & Benson, T. M. (2016). Parity-time symmetric chain resonators.

A simple tight-binding model to study the band-structure of an infinite length Parity-time (PT) symmetric chain of resonators is presented in this paper. In the talk, we will investigate the impact of having a structure of finite length and consider... Read More about Parity-time symmetric chain resonators.

Localized single frequency lasing states in a finite parity-time symmetric resonator chain (2016)
Journal Article
Phang, S., Vukovic, A., Creagh, S. C., Sewell, P., Gradoni, G., & Benson, T. M. (2016). Localized single frequency lasing states in a finite parity-time symmetric resonator chain. Scientific Reports, 6, Article e20499. https://doi.org/10.1038/srep20499

In this paper a practical case of a finite periodic Parity Time chain made of resonant dielectric cylinders is considered. The paper analyzes a more general case where PT symmetry is achieved by modulating both the real and imaginary part of the mate... Read More about Localized single frequency lasing states in a finite parity-time symmetric resonator chain.

Threshold manipulation in parity-time symmetric microresonator chain (2015)
Presentation / Conference Contribution
Phang, S., Vukovic, A., Creagh, S., Benson, T. M., Gradoni, G., & Sewell, P. D. (2015). Threshold manipulation in parity-time symmetric microresonator chain.

This paper analyses the eigenfrequencies of an infinitely long chain of microresonators with PT symmetry. The results show that the depth of modulation of the real part of the refractive index can be used to control the threshold point of the PT stru... Read More about Threshold manipulation in parity-time symmetric microresonator chain.

Parity-time chain of whispering-gallery mode resonators (2015)
Presentation / Conference Contribution
Phang, S., Vukovic, A., Creagh, S., Benson, T. M., Gradoni, G., & Sewell, P. D. (2015). Parity-time chain of whispering-gallery mode resonators.

The paper analyses the dispersion characteristics of an infinitely long PT chain made of whispering gallery resonators with gain/loss modulation. The results show that the appearance of the threshold breaking point depends not only on both of couplin... Read More about Parity-time chain of whispering-gallery mode resonators.

Parity-time symmetric coupled microresonators with a dispersive gain/loss (2015)
Journal Article
Phang, S., Vukovic, A., Creagh, S. C., Benson, T. M., Sewell, P. D., & Gradoni, G. (2015). Parity-time symmetric coupled microresonators with a dispersive gain/loss. Optics Express, 23(9), 11493-11507. https://doi.org/10.1364/oe.23.011493

The paper reports on the coupling of Parity-Time (PT)-symmetric whispering gallery resonators with realistic material and gain/loss models. Response of the PT system is analyzed for the case of low and high material and gain dispersion, and also for... Read More about Parity-time symmetric coupled microresonators with a dispersive gain/loss.

Saturable and dispersive parity-time symmetric directional coupler: a transmission-line modelling study (2014)
Presentation / Conference Contribution
Phang, S., Vukovic, A., Benson, T. M., Creagh, S., Sewell, P., & Gradoni, G. (2014). Saturable and dispersive parity-time symmetric directional coupler: a transmission-line modelling study.

In this paper, numerical modelling of Parity-Time (PT) coupled waveguides is reported. The PT coupled waveguide structure consists of two coupled slab waveguides based on GaAs material with gain/loss material parameter models, including both dispersi... Read More about Saturable and dispersive parity-time symmetric directional coupler: a transmission-line modelling study.

In–out decomposition of boundary integral equations (2013)
Journal Article
Creagh, S. C., Hamdin, H. B., & Tanner, G. (2013). In–out decomposition of boundary integral equations. Journal of Physics A: Mathematical and Theoretical, 46(43), Article 435203. https://doi.org/10.1088/1751-8113/46/43/435203

We propose a reformulation of the boundary integral equations for the Helmholtz equation in a domain in terms of incoming and outgoing boundary waves. We obtain transfer operator descriptions which are exact and thus incorporate features such as diff... Read More about In–out decomposition of boundary integral equations.

Time-modulated gain and loss parity-time symmetric resonators
Presentation / Conference Contribution
Phang, S., Vukovic, A., Creagh, S., Gradoni, G., Sewell, P., & Benson, T. M. (2016). Time-modulated gain and loss parity-time symmetric resonators.

Coupled parity-time symmetric cavities: results from transmission line modelling simulations
Presentation / Conference Contribution
Phang, S., Vukovic, A., Creagh, S., Sewell, P. D., Gradoni, G., & Benson, T. M. (2015). Coupled parity-time symmetric cavities: results from transmission line modelling simulations.

This paper studies the impact of a dispersive gain/loss material model on Parity-Time (PT) coupled microresonator cavity structures using the time-domain Transmission-Line Modelling method. A modal analysis is also performed to compare the modal comp... Read More about Coupled parity-time symmetric cavities: results from transmission line modelling simulations.