Articles in 2020

Enhanced second-harmonic generation is achieved through random quasi-phase-matching in three-dimensional Mie resonant disordered microspheres realized by the bottom-up assembly of barium titanate nanocrystals.

The application of deep learning to the design of photonic structures and devices is reviewed, including algorithm fundamentals.

The limited control of electrons by light has resulted in photonic-driven circuits lagging far behind their electronic counterparts. Now, a technique exploiting coherent control with structured light has been used to sculpt the spatial distribution of electric currents, ushering in vectorized optoelectronic control in semiconductors.

Two independent studies report new organic compounds that offer record rates of reverse intersystem crossing between triplet and singlet excited states. The result is sky-blue organic light-emitting diodes with improved efficiency, stability and reduced efficiency roll-off.

Strongly correlated photon states are achieved using only weak coupling thanks to an ensemble of non-interacting waveguide-coupled atoms and collectively enhanced nonlinear interactions.

The integration of diamond waveguide arrays into an aluminium nitride photonic platform offers hope for the realization of scalable chips for quantum information processing.

Gold atoms are stripped of 72 of their electrons to form nitrogen-like Au⁷²⁺ ions inside extremely hot plasmas by irradiating gold foils and nanowires with highly relativistic femtosecond laser pulses.

An experimental study of the second-harmonic-generation process in a beta barium borate crystal shows that homogeneous optical crystals can exhibit the rich physics of the spin–orbit angular momentum cascade in the nonlinear optical regime.

Engineering of the spatial distribution of currents in a semiconductor is demonstrated using vectorial arrangement of optical fields, enabling an ultrafast magnetic field source.

A method to tune pseudo-magnetic fields for polaritons on a strained metasurface is demonstrated.

Tunable X-ray generation, from ultrathin van der Waals materials impacted by relativistic electrons, is demonstrated.

Using topological singular points, the topological charge of photonic crystals in momentum space is successfully transferred to optical vortex beams in real space.

The Kramers–Kronig approach is applied to high-capacity, free-space terahertz communications, bringing a greatly simplified receiver design.

The photovoltaics market has long been dominated by silicon, but further improvements of these solar cells require novel approaches. Now, triplet–triplet annihilation photon upconversion has been used to harvest photons from below the bandgap of silicon, extending the spectral response and potentially improving the efficiency of these cells.

Launching electrons to the centre of an optical field with a vortex phase profile via extreme-ultraviolet photoionization makes coherent imprinting of the spatial distribution of the vortex beam onto the electron wave packet possible.

Directly relating the complex second-harmonic-generation field to the second-order susceptibility tensor allows tomographic imaging of nonlinear optical contrast at high frame rates.