The electrical properties of topological electronic systems are robust to deformation. Now, scientists have created an optical equivalent of such systems — a room-temperature silicon chip in which infrared light travels around its edge, unaffected by defects (depicted here as melting). This design paves the way for the miniaturization of optical systems through exploiting electronic analogues.Article p1001News & Views p941IMAGE: EMILY EDWARDSCOVER DESIGN: TOM WILSON

Thanks to recent developments, lasers based on fibre media with gain have become simple, reliable and cost effective. Topics covered in this focus include high-power sources, ultrafast fibre lasers, industry’s perspective on the developments in the field over the past decade, applications such as biomedical imaging, and nanotube- and graphene-based saturable absorbers for fibre lasers.

Focus issue: Fibre Lasers

IMAGE: FIANIUM

COVER DESIGN: TOM WILSON

The onset of turbulence and coherence loss in fibre laser radiation is studied and found to originate from the clustering of solitons.Letter p783News & Views p767Interview p840IMAGE: ARTEM OVCHARENKO, TURITSYNA ET AL.COVER DESIGN: TOM WILSON

Researchers in Japan generate tailored terahertz polarization shaped waveforms by employing the optical rectification of a laser pulse whose instantaneous polarization state and intensity are controlled by an optical pulse shaper.Article p724News & Views p678COVER DESIGN: TOM WILSON

The nonlinear interaction of ultrashort laser pulses with a medium can generate trains of attosecond pulses. Here, ultrafast photonic streaking launches successive individual attosecond pulses in different directions, enabling direct experimental access to these pulses, which carry information on the ultrafast dynamics of the medium.Article p651IMAGE: KIM ET AL.COVER DESIGN: TOM WILSON

Achieving broadband photoenergy conversion is critical for developing high-efficiency organic photovoltaics. Scientists report a tandem solar cell that employs a broadband light absorber on nanostructured substrates.Letter p535IMAGE: KINOSHITA ET AL.COVER DESIGN: TOM WILSON

Using suitable shape deformations, scientists demonstrate how to exploit chaotic wave dynamics to greatly enhance the ability of optical resonators to harvest broadband light energy, reporting a six-fold increase with respect to classical resonators of the same volume.

Article p473

News & Views p430

IMAGE: A. FRATALOCCHI AND O. ZAUSALINA

COVER DESIGN: TOM WILSON

Scientists report a polymer-based optoelectronic interface that can restore light sensitivity to the retinas of blind rats, highlighting the potential for retinal implants to be made from all-organic biocompatible materials, rather than inorganic semiconductors such as silicon.

Article p400

IMAGE: NICHOLAS DRING AND LUCA

MARAGLIANO (FONDAZIONE ISTITUTO

ITALIANO DI TECNOLOGIA, GENOVA, ITALY)

COVER DESIGN: TOM WILSON

A view inside an inversion-symmetry-broken double-gyroid photonic crystal containing frequency-isolated Weyl points in its band structure. Weyl points are three-dimensional point degeneracies of linear dispersions; they are higher-dimensional analogues of two-dimensional Dirac points.

News & Views p268; Article p294

IMAGE: LING LU

COVER DESIGN: TOM WILSON

The diffusive spreading of laser light by a disordered collection of submillimetre-sized glass spheres.

Review p188

IMAGE: DIEDERIK AND LEONARDO WIERSMA

COVER DESIGN: TOM WILSON

The cover shows a schematic illustration of a obliquely oriented vertical waveguide formed in a 3D photonic crystal with a stacked stripe structure. This waveguide has enabled the realization of on-demand 3D light guiding in photonic crystals.

Letter p133; News & Views p89

IMAGE: NODA AND ISHIZAKI et al.

COVER DESIGN: TOM WILSON

Using spectrally shaped counter-propagating femtosecond laser pulses, scientists demonstrate spatial and spectral coherent control in an atomic vapour, exciting atoms only at specific controlled locations in space with high resolution.

Letter p38; News & Views p6

IMAGE: BARMES et al.

COVER DESIGN: TOM WILSON