Volume 15 Issue 10, October 2021

The phase of terahertz waves can now be precisely modulated electronically using a chip-based digitally coded phase shifter. The achievement is a step towards chip-scale integrated terahertz technology.

Time-varying metamaterials bring in an extra degree of freedom, enabling applications unachievable by normal metamaterials and opening up new opportunities.

Nearly 100 years after the prediction of Brillouin light-scattering spectroscopy, or Brillouin–Mandelstam light-scattering spectroscopy, the effect has proved itself a powerful tool for decades. Now its application to probing confined acoustic phonons, phononic metamaterials and magnons is reviewed.

Strong lanthanide-doped upconversion luminescence enhancement is achieved by the use of surface molecules which enhance four-photon upconversion emission. The results may lead to new, highly emissive, nanohybrid systems.

Solution-processed infrared lasers that operate at room temperature are a challenge, but now researchers have achieved such a device using colloidal quantum dots.

A transmission scheme for free-space optical communications is shown to be highly robust against turbulence.

A terahertz phase modulator based on the switchable perturbation resonance in two-dimensional electron gas is demonstrated. Phase manipulation with precision ranging from 2° to 5° is obtained at frequencies in the range from 0.26 to 0.27 THz.

Quantum noise is suppressed by a bound state in the continuum (BIC) approach, enabling a microlaser with narrow linewidth compared to other small lasers.

Electron non-stationary tunnelling dynamics is probed by the attoclock with the two-colour phase-of-phase photoelectron spectroscopy. Contrary to the case of static tunnelling, angle-to-time mapping in attoclock is found to be not angularly uniform.

A hybrid photonic–atomic device based on the integration of tapered nanoscale and mechanically suspended waveguides with hot vapour is reported, demonstrating a drastic reduction in absorption linewidth and improved vapour coherence time.

This study reveals the importance of host–guest interactions for effective multiple-resonance thermally activated delayed fluorescence in organic light emitters.