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Time reversal symmetry breaking gives rise to magnetic circular dichroism and Faraday rotation in graphene. The authors use terahertz magneto-electro-optical spectroscopy to demonstrate that electrostatic doping at a fixed magnetic field allows inversion of magnetic circular dichroism and Faraday rotation.

Whole-genome sequencing analysis of 81 prehistoric individuals reveals how the genetic makeup of people from the North Pontic region was influenced by waves of migration during the Eneolithic period and Early Bronze Age.

This Review highlights fundamental optical phenomena that have been redefined at the nanoscale by anisotropic polaritons, including anomalous cases of refraction, reflection and focusing.

Polaritonic Fourier crystal provides harmonic modulation of the polariton momentum in a pristine polaritonic waveguide. Authors employ hexagonal boron nitride and near-field imaging to probe Bloch waves of phonon-polaritons in the Fourier crystal.

Genome-wide data from 166 East Asian individuals dating to between 6000 bc and ad 1000 and from 46 present-day groups provide insights into the histories of mixture and migration of human populations in East Asia.

Researchers observe directional strong coupling on the nanoscale between hyperbolic phonon polaritons and pentacene molecules.

Canalized polaritons are light-matter excitations characterized by intrinsic collimation of electromagnetic energy along a specific crystal axis. Here, the authors report the observation of intrinsically canalized phonon polaritons in a single thin layer of a van der Waals crystal, LiV₂O₅.

Ancient DNA reveals how the explosive expansion of Yamnaya steppe pastoralists began with a small community north of the Black Sea speaking ancestral Indo-European, and detects genetic links with Anatolian speakers, stemming from a common Indo-Anatolian homeland in the North Caucasus–lower Volga region.

Time-domain interferometry and near-field scanning microscopy are used to investigate infrared phonon polaritons exhibiting hyperbolic dispersion. Negative phase velocity and group velocity as small as 0.002c are confirmed.

Phonon polaritons can be harnessed for SEIRA spectroscopy. Here, the authors demonstrate a compact on-chip phononic SEIRA platform based on a h-BN/graphene/h-BN heterostructure atop a metal split-gate that serves both as a SEIRA substrate and as a room-temperature infrared detector.

Near-field photocurrent nanoscopy is used for imaging strongly confined terahertz graphene plasmons with linear dispersion.

Here the authors adapt a STEM-EELS system to probe energy loss down to 100 meV, and apply it to map phononic states in hexagonal boron nitride, revealing that the electron loss is dominated by hyperbolic phonon polaritons.

Genome-wide ancient DNA data from 225 individuals who lived in southeastern Europe between 12000 and 500 bc reveals that the region acted as a genetic crossroads before and after the arrival of farming.

The directional propagation of phonon polaritons has been demonstrated in various twisted van der Waals materials. Here, the authors report a complementary type of directional polariton propagation by visualizing unidirectional ray polaritons in twisted asymmetric stacks of α-MoO3 and/or β-Ga2O3.

The real-space imaging of propagating THz polaritons, coupled light-matter excitations, in topological insulators has been elusive so far. Here, the authors report spectroscopic THz near-field images of the topological insulator Bi₂Se₃ revealing polaritons formed by coupling of THz radiation to optical phonons and various charge carriers.

Photonic crystals can steer, shape, and sculpture the flow of photons. Here, the author fabricate a deep-subwavelength photonic crystal slab that supports ultra-confined phonon polaritons, by patterning a nanoscale hole array in h-BN.

Near-field optical microscopy reveals unique nanoscale domain structures of Moiré patterns in minimally twisted bilayer graphene via the photothermoelectric effect.

Momentum mismatch prevents efficient coupling between free space photons and hyperbolic phonon polaritons. The authors show, using far-field infrared spectroscopy, infrared nanoimaging and numerical simulations, that resonant metallic antennas can efficiently launch hyperbolic phonon polaritons in thin h-BN slabs.

The direction of polariton canalization—its diffractionless propagation—in twisted bilayers at the magic angle is hindered by the lack of multiple magic angles. By controlling the twist angles between three α-MoO₃ layers, reconfigurable and spectrally robust polariton canalization along any in-plane direction is demonstrated.

Excitation and gate tuning of terahertz plasmons in dual-layer graphene integrated into on-chip telecom photonic waveguides using infrared lasers has now been demonstrated. This may open the door to atomically thick optoelectronic devices for security, tomography or data processing.

Observation of the anisotropic propagation of polaritons along the surface of layered, semiconducting α-MoO₃ confirms the existence of this phenomenon in natural materials.

Real-space mid-infrared nanoimaging reveals vibrational strong coupling between molecules and propagating phonon polaritons in unstructured, thin hexagonal boron nitride layers, which could provide a platform for testing strong coupling and local control of chemical properties.

The spectral range of long-lived and confined phonon polaritons in a polar van der Waals crystal is shown to be tunable by intercalation of Na atoms, expanding their potential for nanophotonic applications in the mid-infrared domain.

Genome-wide sequencing of 56 ancient hunter-gatherer and early farmer individuals from Stone Age Central and Eastern Europe reveals striking population continuity in the east in contrast to central Europe that displays extensive admixture.

By modulating the dimensions of magnonic crystals, their transmission properties in the microwave regime may be tuned and so applications including information processing are anticipated. The authors here show reflection-less spin-wave propagation may be realised in a width-modulated waveguide.

Fast and energy-efficient control of magnon transport in magnonic crystals is one of the main challenges of modern magnonics. High performances for voltage control are expected but have so far only been predicted theoretically and investigated numerically. In this paper, the authors report of the first experimental realization of voltage-controlled magnon currents in a dynamic electromagnonic crystal.

The experimental observation of plasmon-polaritons in charge-neutral bilayer graphene sparked interest for plasmonic and superconducting devices. Here, simulations predict that plasmon-polaritons possessing either transverse magnetic or electric polarization arise under an applied magnetic field in charge-neutral monolayer graphene.