Volume 13 Issue 9, September 2019

Engineering the thermal profile of a polymer by means of conducting microwires provides a path towards versatile tunable optical elements.

Dielectric antennas and metasurfaces open up new opportunities for future applications in advanced optoelectronics, light detection and ranging for autonomous vehicles, fluorescence-enhancing substrates for bioimaging and many more.

By using a single-quantum-well active region with a unique well–cladding design to suppress non-radiative recombination and enhance radiative recombination, light-emitting diodes with close to unity internal quantum efficiency at a low current density of <10⁻⁴ A cm⁻² are demonstrated.

Combining resonant enhancement with nanophotonic mode engineering in a silicon nitride microring resonator allows spectral translation of a continuous-wave signal from the telecom band (~1,550 nm) to the visible band (~650 nm) through cavity-enhanced four-wave mixing with a translation efficiency of (30.1 ± 2.8)% at a pump power of (329 ± 13) μW.

Perovskite-like materials enable different X-ray detection performance along different crystal directions. A low detection limit of 55 nGy_air s⁻¹ is demonstrated.

Photoacoustic detection highly localized with a pulsed ultraviolet laser based on the Grüneisen relaxation effect allows water-background suppressed mid-infrared (MIR) imaging of lipids and proteins at ultraviolet resolution, at least an order of magnitude finer than the MIR diffraction limits.

Efficient power transfer from the pump to the soliton can be achieved through field coupling between two optical resonators, allowing soliton frequency comb generation with tens-to-hundreds-of-fold improvement in conversion efficiency compared with a traditional single-resonator comb.

The distribution of Berry charge over a ring of exceptional points, called a Weyl exceptional ring, is experimentally demonstrated.

A method to control the polarization of a Compton gamma-ray beam is developed. By using a free-electron laser oscillator with two helical undulator magnets of opposite helicities, Compton gamma-ray beams with a polarizability of 0.97 are generated.

A two-step sequential broadband nanofocusing technique offers an external efficiency of ~50% over nearly all the visible range on a fibre-coupled plasmonic nanowire probe. Its integration with a scanning tunnelling microscope realizes lens-free tip-enhanced Raman spectroscopy with 1 nm spatial resolution.

An all-photonic quantum repeater is demonstrated by manipulating state-of-the-art 12-photon interferometry. The enhancement of entanglement-generation rate compared with parallel entanglement swapping proves the feasibility of the concept.

Using microheaters and a genetic algorithm optimization, deterministic phase-front shaping through a planar thermo-optical module can be realized, complementing the existing optical shaping toolbox by offering low-chromatic-aberration, polarization-insensitive and transmission-mode components.