Volume 18 Issue 2, February 2024

The fast response and efficiency of plastic scintillators are severely degraded by the preferential population of slow triplet excited states in luminescence centres, such as in dye molecules. This issue can be solved by hot exciton manipulation, which avoids population of the lowest triplet state.

Nonlinear optical resonators allow the coherent conversion of photons, yet fabrication tolerances limit their wavelength accuracy. Introducing periodic modulation in ring resonators is shown to allow robust and predictable selection of the converted photons.

The progress made in developing light-emitting technologies that are wearable, attachable or implantable is reviewed and potential applications and challenges are discussed.

A mid-infrared dual-comb system capable of nanosecond time-resolved spectral measurements is realized by using a singly resonant optical parametric oscillator that allows an efficient conversion of an input dual-comb pump at 1 µm into an idler dual comb in the mid-infrared regime.

Electrically injected charges can effectively contribute to optical gain in perovskite light-emitting diodes under optical and electrical co-excitation.

A terahertz focal-plane array based on a two-dimensional array of plasmonic photoconductive nanoantennas offers high-quality imaging in the terahertz region.

Self-configuring meshes of integrated Mach–Zehnder interferometers determine the optimal communication channels through unknown optical media, with the resulting modes showing crosstalk below –30 dB.

By implanting ¹¹⁷Sn, a fibre-packaged nanophotonic diamond waveguide with optically addressable hyperfine transitions separated by 452 MHz is demonstrated. This enables the formation of a spin-gated optical switch and achieving a waveguide-to-fibre extraction efficiency of 57%.

Researchers overcome the typical scintillator trade-off between high efficiency and speed. In organic scintillators, researchers drove hot excitons into fast singlet emission states without involving the lowest triplet states, which led to a fast radiative lifetime and strong light yield that may be applicable to ultrafast detection and imaging.

Controlling the intrinsic doping of lead-free perovskites enables near-infrared LEDs emitting at 948 nm with a peak radiance of 226 W sr^–1 m^–2 and a half-lifetime of 39.5 h.

Luminescence solar concentrators are improved by using a laminated structure that creates a practically non-decaying optical ‘guard rail’ for light. Design rules enabled external quantum efficiencies as high as 45% for 450 nm light, yielding a device efficiency of 7.6%, probably useful for energy-harvesting windows.

Dipole–dipole interactions in mixed-phase CdZnSeS quantum dots enable the effective orientation of the quantum dots and improved photon out-coupling when employed in a light emitting diode.

Researchers demonstrate nonlinear wavelength converters whose output wavelengths are controlled with high accuracy by bandgap-protected wavenumber selectivity. Output frequencies are continuously tuned by nearly 300 GHz without compromising efficiency.

Solution-processed copper–iodide clusters are employed as efficient emitters for warm white LEDs with external quantum efficiency of 19.1%.