| 1. |
- Gelens, Lendert, et al.
(författare)
-
Impact of nonlocal interactions in dissipative systems: Towards minimal-sized localized structures
- 2007
-
Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 75:6, s. 063812-
-
Tidskriftsartikel (refereegranskat)abstract
- In order to investigate the size limit of spatial localized structures in a nonlinear system, we explore the impact of linear nonlocality on their domains of existence and stability. Our system of choice is an optical microresonator containing an additional metamaterial layer in the cavity, allowing the nonlocal response of the material to become the dominating spatial process. In that case, our bifurcation analysis shows that this nonlocality imposes another limit on the width of localized structures going beyond the traditional diffraction limit.
|
|
| 2. |
- Ginis, Vincent, et al.
(författare)
-
Creating electromagnetic cavities using transformation optics
- 2012
-
Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 14, s. 033007-
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the potential of transformation optics for the design of novel electromagnetic cavities. First, we determine the dispersion relation of bound modes in a device performing an arbitrary radial coordinate transformation and we discuss a number of such cavity structures. Subsequently, we generalize our study to media that implement azimuthal transformations, and show that such transformations can manipulate the azimuthal mode number. Finally, we discuss how the combination of radial and azimuthal coordinate transformations allows for perfect confinement of subwavelength modes inside a cavity consisting of right-handed materials only.
|
|
| 3. |
- Lambrechts, L., et al.
(författare)
-
Transformation optics for surface phenomena: Engineering the Goos-Hänchen effect
- 2017
-
Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 95:3, s. Article no 035427 -
-
Tidskriftsartikel (refereegranskat)abstract
- Transformation optics, a geometrical recipe for metamaterial design, was originally conceived as a tool to smoothly modify the trajectory of light using continuous coordinate transformations. Here, we show how discontinuous transformations can be used as a geometric framework to understand and manipulate phenomena at the surface of nanophotonic structures. In particular, we show how the Goos-Hänchen shift - a lateral shift exhibited by totally reflected beams - can be tailored and we provide a classification and complete analytical description of this effect in existing complex media.
|
|
| 4. |
- Tassin, Philippe, 1982, et al.
(författare)
-
Dissipative structures in left-handed material cavity optics
- 2007
-
Ingår i: Chaos. - : AIP Publishing. - 1089-7682 .- 1054-1500. ; 17:3, s. 037116-
-
Tidskriftsartikel (refereegranskat)abstract
- We study the spatiotemporal dynamics of spatially extended nonlinear cavities containing a left-handed material. Such materials, which have a negative index of refraction, have been experimentally demonstrated recently, and allow for novel electromagnetic behavior. We show that the insertion of a left-handed material in an optical resonator allows for controlling the value and the sign of the diffraction coefficient in dispersive Kerr resonators and degenerate optical parametric oscillators. We give an overview of our analytical and numerical studies on the stability and formation of dissipative structures in systems with negative diffraction.
|
|
| 5. |
- Van Der Sande, Guy, et al.
(författare)
-
Two-dimensional phase-space analysis and bifurcation study of the dynamical behaviour of a semiconductor ring laser
- 2008
-
Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 1361-6455 .- 0953-4075. ; 41:9, s. 095402-
-
Tidskriftsartikel (refereegranskat)abstract
- A basic rate equation model of a quantum-well semiconductor ring laser is reduced to two equations using asymptotic methods. The reduced model allows for analytical expressions of the bifurcation points, which will simplify future model parameter estimations, and motivates a two-dimensional phase-space description of the dynamical behaviour. An analysis of the bifurcation scenarios in different parameter regimes is pursued. Physical conditions for the emergence of the operating regimes are assessed quantitatively in terms of saturation processes and backscattering mechanisms.
|
|
| 6. |
- Viaene, Sophie, 1990, et al.
(författare)
-
Do Optomechanical Metasurfaces Run Out of Time?
- 2018
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:19
-
Tidskriftsartikel (refereegranskat)abstract
- Artificially structured metasurfaces make use of specific configurations of subwavelength resonators to efficiently manipulate electromagnetic waves. Additionally, optomechanical metasurfaces have the desired property that their actual configuration may be tuned by adjusting the power of a pump beam, as resonators move to balance pump-induced electromagnetic forces with forces due to elastic filaments or substrates. Although the reconfiguration time of optomechanical metasurfaces crucially determines their performance, the transient dynamics of unit cells from one equilibrium state to another is not understood. Here, we make use of tools from nonlinear dynamics to analyze the transient dynamics of generic optomechanical metasurfaces based on a damped-resonator model with one configuration parameter. We show that the reconfiguration time of optomechanical metasurfaces is not only limited by the elastic properties of the unit cell but also by the nonlinear dependence of equilibrium states on the pump power. For example, when switching is enabled by hysteresis phenomena, the reconfiguration time is seen to increase by over an order of magnitude. To illustrate these results, we analyze the nonlinear dynamics of a bilayer cross-wire metasurface whose optical activity is tuned by an electromagnetic torque. Moreover, we provide a lower bound for the configuration time of generic optomechanical metasurfaces. This lower bound shows that optomechanical metasurfaces cannot be faster than state-of-the-art switches at reasonable powers, even at optical frequencies.
|
|
| 7. |
- Viaene, Sophie, 1990, et al.
(författare)
-
Mitigating optical singularities in coordinate-based metamaterial waveguides
- 2017
-
Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 95:15, s. Article Number: 155412-
-
Tidskriftsartikel (refereegranskat)abstract
- Transformation optics has revolutionized our approach to material design in several scientific disciplines by determining the material properties that implement the desired effects of a coordinate transformation. Unfortunately, the performance of several coordinate-based devices, such as beam splitters and invisibility cloaks, suffers from the necessary implementation of singularities with extreme material parameters. Here, we make use of transformation optics to eliminate these singularities in an isotropic way for the improvement of coordinate-based metamaterial waveguides. In particular, singularities that lead to vanishing material properties are softened with a global rescaling of the coordinates, while singular terms that lead to infinite material properties are strategically replaced by well-behaved curve factors. Detailed full-wave simulations confirm that the resulting waveguide devices are as efficient as their singular counterparts despite the fact that they consist of materials with much more moderate optical properties.
|
|
