Volume 13 Issue 7, July 2019

The time it takes for a particle to tunnel through a potential barrier, and even the interpretation of this phenomenon, have long drawn debate. By performing an attosecond angular streaking experiment in connection with ab initio calculations, researchers have concluded that tunnelling is instantaneous for atomic hydrogen.

Josephson vortices are observed at the boundary between two exciton-polariton condensates, with lasers used to create the required local phase twist. The finding opens new opportunities for exploring fundamental physics and engineering novel quantum devices.

Emerging data reveal that amyloid fibrils possess intrinsic photonic activity, showing luminescence over a wide range of the electromagnetic spectrum from the ultraviolet to the near-infrared.

It is possible to regulate random lasers by controlling and manipulating their properties, including the number and spatial positions of their lasing modes, and the lasing wavelength and the modal size over wide ranges. Performances comparable with non-random optical cavities with 2D photonic crystals are reported.

Stereo images of gold nanoparticles in a pyramid shape are reconstructed from X-ray coherent diffraction patterns. Depth information is retrieved by computing disparity maps without a priori knowledge of the sample shape.

A photonic-crystal platform enables attojoule-energy electro-optic modulators and amplifier-free photoreceivers.

Planar perovskite solar cells that have been passivated using the organic halide salt phenethylammonium iodide are shown to have suppressed non-radiative recombination and operate with a certified power conversion efficiency of 23.3%.

By entangling the phase and spin of light, a synthetic metasurface is shown to be able to coherently manipulate the valley-exciton-locked chiral emission in monolayer tungsten disulfide at room temperature. The findings will be of benefit to advanced room-temperature and free-space nonlinear, quantum and valleytronic nanodevices.

Two optical signatures of amyloid fibres—luminescence in the blue and a near-infrared signal, which can be observed in in vitro and in vivo tissues—are reported. The findings allow for staining-free characterization of amyloid deposits in human samples and could open the door to innovative diagnostic strategies for neurodegenerative diseases.

Interferometric scattering microscopy is employed to track proteins in live cell membranes, demonstrating tracking of transmembrane epidermal growth factor receptors with nanometre precision in all three dimensions at up to microsecond speeds and for durations of tens of minutes.

All-optical control of the topological excitations of a superfluid of light is demonstrated in a high-quality-factor semiconductor microcavity. Recovery of superfluid behaviour at high polariton densities and bosonic Josephson vortices are observed.

Femtosecond laser pulses can generate self-organized nonlinear gratings in nanophotonic waveguides, providing both quasi-phase-matching and group-velocity matching for second-harmonic generation, and enabling simultaneous χ² and χ³ nonlinear processes for laser-frequency-comb stabilization.