19 research outputs found
Causality effects on accelerating light pulses
We study accelerating and decelerating shape-preserving temporal Airy wave-packets propagating in dispersive media. We explore the effects of causality, and find that, whereas decelerating pulses can asymptotically reach zero group velocity, pulses that accelerate towards infinite group velocity inevitably break up, after a specific critical point. The trajectories and the features of causal pulses are analyzed, along with the requirements for the existence of the critical point and experimental schemes for its observation. Finally, we show that causality imposes similar effects on accelerating pulses in the presence of local Kerr-like nonlinearities
Phase Retrieval of Vortices in Bose-Einstein Condensates
We propose and demonstrate numerically a measurement scheme for complete
reconstruction of the quantum wavefunctions of Bose-Einstein condensates,
amplitude and phase, from a time of flight measurement. We identify a
fundamental ambiguity present in the measurement of vortices and show how to
overcome it by augmenting the measurement to allow reconstruction of
matter-wave vortices and arrays of vortices
Probing topological invariants in the bulk of a non-Hermitian optical system
Topological insulators are insulating in the bulk but feature conducting
states on their surfaces. Standard methods for probing their topological
properties largely involve probing the surface, even though topological
invariants are defined via the bulk band structure. Here, we utilize
non-hermiticy to experimentally demonstrate a topological transition in an
optical system, using bulk behavior only, without recourse to surface
properties. This concept is relevant for a wide range of systems beyond optics,
where the surface physics is difficult to probe
第923回千葉医学会例会・第11回磯野外科例会
Topological, NOON, with disorder Originally published in Optica on 20 September 2016 (optica-3-9-925
Topological Insulator Lasers
We present, in theory and experiments, the first Topological Insulator Lasers: lasers where the cavity acts as a superconductor for light , maintaining slope high efficiency even in the presence of defects and disorder