240 citations · 1.9k across the 38 of their papers we have counts for
16 papers · 1 filter
Exploring complex graphs using three-dimensional quantum walks of correlated photons
Max Ehrhardt, Robert Keil, Lukas J. Maczewsky +3
Graph representations are a powerful concept for solving complex problems across natural science, as patterns of connectivity can give rise to a multitude of emergent phenomena. Gr…
Hanbury Brown and Twiss anticorrelation in disordered photonic lattices
H. Esat Kondakci, Lane Martin, Robert Keil +5
We report measurements of Hanbury Brown and Twiss correlation of coherent light transmitted through disordered one-dimensional photonic lattices. Although such a lattice exhibits t…
Hybrid waveguide-bulk multi-path interferometer with switchable amplitude and phase
Robert Keil, Thomas Kaufmann, Thomas Kauten +5
We design and realise a hybrid interferometer consisting of three paths based on integrated as well as on bulk optical components. This hybrid construction offers a good compromise…
Electric-field-induced energy tuning of on-demand entangled-photon emission from self-assembled quantum dots
Jiaxiang Zhang, Eugenio Zallo, Bianca Höfer +6
The scalability of quantum dot based non-classical light sources relies on the control over their dissimilar emission energies. Electric fields offer a promising route to tune the…
Direct measurement of second-order coupling in a waveguide lattice
Robert Keil, Benedikt Pressl, René Heilmann +3
We measure the next-nearest-neighbour coupling in an array of coupled optical waveguides directly via an integrated eigenmode interferometer. In contrast to light propagation exper…
Universal sign-control of coupling in tight-binding lattices
Robert Keil, Charles Poli, Matthias Heinrich +4
We present a method of locally inverting the sign of the coupling term in tight-binding systems, by means of inserting a judiciously designed ancillary site and eigenmode matching…
Compact surface Fano states embedded in the continuum of waveguide arrays
Steffen Weimann, Yi Xu, Robert Keil +5
We describe theoretically and observe experimentally the formation of a surface state in a semi-infnite waveguide array with side-coupled waveguide, designed to simultaneously achi…
Biphoton generation in quadratic waveguide arrays: A classical optical simulation
Markus Gräfe, Alexander. S. Solntsev, Robert Keil +6
Quantum entanglement, the non-separability of a multipartite wave function, became essential in understanding the non-locality of quantum mechanics. In optics, this non-locality ca…
Solitons in geometric potentials
Yaroslav V. Kartashov, Alexander Szameit, Robert Keil +2
We show that the geometrically-induced potential existing in undulated slab waveguides dramatically affects the properties of solitons. In particular, whereas solitons residing in…
Amorphous Photonic Lattices: Band Gaps, Effective Mass and Suppressed Transport
Mikael Rechtsman, Alexander Szameit, Felix Dreisow +4
We present, theoretically and experimentally, amorphous photonic lattices exhibiting a band-gap yet completely lacking Bragg diffraction: 2D waveguides distributed randomly accordi…
Geometric potential and transport in photonic topological crystals
Alexander Szameit, Felix Dreisow, Matthias Heinrich +4
We report on the experimental realization of an optical analogue of a quantum geometric potential for light wave packets constrained on thin dielectric guiding layers fabricated in…
Wave localization at the boundary of disordered photonic lattices
A. Szameit, Y. V. Kartashov, P. Zeil +7
We report on the experimental observation of reduced light energy transport and disorder-induced localization close to a boundary of a truncated one-dimensional (1D) disordered pho…
Two-dimensional solitons at interfaces between binary superlattices and homogeneous lattices
M. Heinrich, Y. V. Kartashov, L. P. R. Ramirez +7
We report on the experimental observation of two-dimensional surface solitons residing at the interface between a homogeneous square lattice and a superlattice that consists of alt…
Observation of two-dimensional superlattice solitons
M. Heinrich, Y. V. Kartashov, L. P. R. Ramirez +7
We observe experimentally two-dimensional solitons in superlattices comprising alternating deep and shallow waveguides fabricated via the femtosecond laser direct writing technique…
Nonlinearity-induced broadening of resonances in dynamically modulated couplers
A. Szameit, Y. V. Kartashov, M. Heinrich +7
We report the observation of nonlinearity-induced broadening of resonances in dynamically modulated directional couplers. When the refractive index of the guiding channels in the c…
Observation of two-dimensional coherent surface vector lattice solitons
M. Heinrich, Y. V. Kartashov, A. Szameit +6
We report the first experimental observation of vector surface solitons, which form at the edge and in the corner of two-dimensional laser-written waveguide arrays. These elliptica…