CELES is a freely available MATLAB toolbox to simulate light scattering by many spherical particles. Aiming at high computational performance, CELES leverages block-diagonal preconditioning, a lookuptable approach to evaluate costly functions and massively parallel execution on NVIDIA graphics processing units using the CUDA computing platform. The combination of these techniques allows to efficiently address large electrodynamic problems (>10 4 scatterers) on inexpensive consumer hardware. In this paper, we validate near-and far-field distributions against the well-established multi-sphere T -matrix (MSTM) code and discuss the convergence behavior for ensembles of different sizes, including an exemplary system comprising 10 5 particles.

The on-chip integration of quantum light sources and nonlinear elements constitutes a major step toward scalable photon-based quantum information processing and communication. In this work we demonstrate the potential of a hybrid technology that combines organic-molecule-based quantum emitters and dielectric chips consisting of ridge waveguides and grating far-field couplers. In particular, dibenzoterrylene molecules in thin anthracene crystals are used as single-photon sources, exhibiting long-term photostability, easy fabrication methods, almost unitary quantum yield, and lifetime-limited emission at cryogenic temperatures. We couple such single emitters to silicon nitride ridge waveguides, showing a coupling efficiency of up to 42 ± 2% over both propagation directions. Our results open a novel path toward a fully integrated and scalable photon-processing platform.

Tremendous enhancement of light-matter interaction in plasmonic-dielectric hybrid devices allows for non-linearities at the level of single emitters and few photons, such as single photon transistors. However, constructing integrated components for such devices is technologically extremely challenging. We tackle this task by lithographically fabricating an on-chip plasmonic waveguide-structure connected to far-field in- and out-coupling ports via low-loss dielectric waveguides. We precisely describe our lithographic approach and characterize the fabricated integrated chip. We find excellent agreement with rigorous numerical simulations. Based on these findings we perform a numerical optimization and calculate concrete numbers for a plasmonic single-photon transistor.

We employed this system to investigate, in real-time on a brain-wide scale, the onset and propagation of acute seizures, as induced by the convulsant drug pentylenetetrazol (PTZ), avoiding detrimental visual stimulation on a highly susceptible system such as an epileptic brain. At a moderate PTZ concentration we observed a widespread increase in nervous activity synchronization with the progression of the exposure time to the drug, particularly in the optic tectum, associated with an unexpected synchronization decrease happening in small spatially-defined areas. At saturating PTZ concentrations we instead observed a brain-wide functional connectivity reorganization and the emergence of distinctive phases of ictal and postictal activity. During the ictal phase the degree of synchronization in the neuronal activity dramatically increases in the whole-brain. On the contrary, the degree of neuronal synchrony in the postictal phase resembles the control condition, with the exception of the dorsal thalamus, where it increases, and subregions of the spinal cord, where it unexpectedly decreases.The volumetric frame rate of our system allowed us to observe the emergence of previously unreported fast rhythmic ictal waves propagating in postero-anterior direction, which we termed caudo-rostral ictal waves (CRIWs), spanning across the whole larval encephalon in about 1 s during the ictal phase.In conclusion, the presented 2P LSF microscope design affords high spatio-temporal resolution while avoiding visual stimuli and allows unprecedented access to whole zebrafish brain epileptic dynamics.