Volume 16 Issue 9, September 2022

Multilayered ferroelectric NbOI₂ crystals with sub-100-nm thickness exhibit efficient second harmonic generation, paving the way for on-chip nonlinear optical components.

The hardest barrier in the way to topological control over light with magnetic fields is extremely weak magneto-optic coupling. Now, strong light-matter coupling in an optical cavity has been used to reach record energy splitting values for photonic spins in magnetic fields. This is a potential game changer for topological photonics.

The presence of topologically protected edge states is usually determined by angular-resolved photoelectron spectroscopy, requiring clean surfaces and ultrahigh vacuum. Now, an all-optical technique, based on high-harmonic radiation, has been shown to detect topological phase transitions under ambient conditions.

A new method enables precise control of spin qubits in diamond by selectively activating them with a laser beam, thus paving the way to the control of spin qubits in dense arrays for applications in quantum technology.

Optical fibres can now directly generate a variety of Bessel beams thanks to custom-designed, intricate 3D-printed structures applied to their tips.

Researchers demonstrate a method based on circularly polarized laser-field-driven high-harmonic generation for probing non-trivial and trivial topological phases in a three-dimensional topological insulator.

Researchers exploit the quadratic nonlinearity of lithium niobate nanowaveguides and demonstrate cavity-free all-optical switching. Switching energies down to 80 fJ, switching times down to ~46 fs and energy–time products of 3.7 × 10⁻²⁷ J s are shown.

Researchers show spin-susceptibility in monolayer MoSe₂ and demonstrate giant effective valley Zeeman splitting and nonlinearity for trion-polaritons.

Near-infrared perovskite light-emitting diodes with extrapolated device lifespans on the scale of years are achieved by the use of a dipolar molecular stabilizer.

Strained NbOI₂ flakes with a thickness of 20 nm exhibit a record SHG absolute conversion efficiency of >0.2% and an effective bulk-like nonlinear susceptibility of 1.1 × 10⁻⁹ m V⁻¹ at the fundamental wavelength of 1,050 nm. The spatial profile of the polarized second-harmonic generation response can be tuned by the fundamental wavelength.

A tilted plasmonic nanocavity enables shortening of the luminescence decay time of a rare-earth-doped nanoparticle to sub-50 ns. High quantum efficiency enhancement, chiral polarization and directional far-field emission are maintained.

Up to six photons in a Greenberger–Horne–Zeilinger state are sequentially generated by using a Rydberg superatom—a mesoscopic atomic ensemble under the condition of strong Rydberg blockade. The efficiency scaling factor for adding one photon is 0.27.

Microwave-driven holonomic quantum gates on an optically selected electron spin in a nitrogen-vacancy centre in diamond are demonstrated. Optically addressable entanglement is generated between the electron and adjacent nitrogen nuclear spin.