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Journals and Conferences
Parity-time (PT) symmetric periodic structures, near the spontaneous PT-symmetry breaking point, can act as unidirectional invisible media. In this regime, the reflection from one end is diminished while it is enhanced from the other. Furthermore, the transmission coefficient and phase are indistinguishable from those expected in the absence of a grating.… (More)
We investigate plasmon resonances in gold nanoparticles to enhance the quantum yield of upconverting materials. For this purpose, we use a rate equation model that describes the upconversion of trivalent erbium based upconverters. Changes of the optical field acting on the upconverter and the changes to the transition probabilities of the upconverter in the… (More)
Within all physical disciplines, it is accepted that wave transport is predetermined by the existence of disorder. In this vein, it is known that ballistic transport is possible only when a structure is ordered, and that disorder is crucial for diffusion or (Anderson-)localization to occur. As this commonly accepted picture is based on the very foundations… (More)
We analyze the impact of loss in lattices of coupled optical waveguides and find that, in such a case, the hopping between adjacent waveguides is necessarily complex. This results not only in a transition of the light spreading from ballistic to diffusive, but also in a new kind of diffraction that is caused by loss dispersion. We prove our theoretical… (More)
In this work, we discuss the management of radiation loss in photonic waveguides. As an experimental basis, we introduce a new technique of fabricating waveguides with tunable loss, which is particularly useful when implementing non-Hermitian (PT-symmetric) systems. To this end, we employ laser-written waveguides with a transverse sinusoidal modulation,… (More)
The procedure used in our previous publication [Opt. Express 20, 271, (2012)] to calculate how coupling to a spherical gold nanoparticle changes the upconversion luminescence of Er(3+) ions contained several errors. The errors are corrected here.
Shi and colleagues found that pyroptosis is abolished in Gsdmd-deficient macrophages (a type of immune cell) exposed to activators of canonical inflammasomes for short times. Kayagaki et al. present similar results; but after prolonged incubation, which may better reflect physiological processes, they no longer detected differences between the pyroptotic… (More)
We report, in theory and experiment, on a new class of optical beams that are radially self-accelerating and nondiffracting. These beams continuously evolve on spiraling trajectories while maintaining their amplitude and phase distribution in their rotating rest frame. We provide a detailed insight into the theoretical origin and characteristics of radial… (More)
A comparison between light dynamics in Pℐ -symmetric and passive optical coupler is presented. We show that, apart from an overall damping factor, the dymanics in the passive coupler fully reproduce thePℐ -symmetric ones.
Common solar cells used in photovoltaic modules feature metallic contacts which partially block the sunlight from reaching the semiconductor layer and reduce the overall efficiency of the modules. Diffractive optical elements were generated in the bulk glass of a photovoltaic module by ultrafast laser irradiation to direct light away from the contacts.… (More)