Scanning electron microscope image of a row of nanopillar semiconductor lasers, after removing the gold encapsulation. Such lasers have diameters on the scale of one hundred nanometres or so and offer a route towards the realization of energy-efficient, miniature sources of laser light for applications in data communications and computing.

Review Article p908

IMAGE: M. T. HILL, A. SUVOROVA,

UNIVERSITY OF WESTERN AUSTRALIA

COVER DESIGN: SAMANTHA WHITHAM

The field profile of a topologically-protected one-way edge mode flowing around a corner and an obstacle. The edge mode is excited close to the bottom interface between the metallic boundary and a photonic crystal with a topological bandgap.

Review Article p821; Editorial p809

IMAGE: LING LU AND JOHN JOANNOPOULOS, MIT

COVER DESIGN: SAMANTHA WHITHAM

3D visualization of a Peregrine soliton, which can occur in nonlinear fibre optics. This and other curious freak wave phenomena are a topic of this month's review.

Review Article p755

IMAGE: GOËRY GENTY

COVER DESIGN: SAMANTHA WHITHAM

Rubidium atoms (balls) become quantum entangled (visualized as links) when probed by laser light (red glow) inside an optical cavity. By forging quantum connections between the atoms, the intrinsic quantum noise of the atoms can be squeezed ten times below the standard quantum limit.

Article p731

IMAGE: STEVEN BURROWS, JILA

COVER DESIGN: SAMANTHA WHITHAM

Time-resolved Raman scattering enhanced by the use of gold nanoparticles makes it possible to observe the vibrations of a single molecule.

Article p650;

News & Views p589

IMAGE: DMITRY FISHMAN

COVER DESIGN: TOM WILSON

Artistic depiction of entanglement between particle-like and wave-like quantum states, which two independent groups have reported concurrently.

Article p564; Article p570

IMAGE: MARCO BELLINI (INO-CNR, ITALY)

COVER DESIGN: TOM WILSON

Terahertz quantum cascade lasers can now generate high-power, broadband frequency combs. The trick is to modify the laser cavity by using a waveguide with a chirped corrugation to compensate for dispersion. This generates a comb featuring a terahertz power of 5 mW spread across 70 lines.

Article p462

IMAGE: YAN LIANG, L2MOLECULE.COM

COVER DESIGN: TOM WILSON

Artistic rendition of charge transfer interface in bulk heterojunction polymer:fullerene solar cells. Even in relatively disordered systems, preferential orientation (face on) of polymer chains (blue) with respect to the fullerene domain (brown) leads to a high photovoltaic performance.

Article p385

IMAGE: TUMBLESTON ET AL.

COVER DESIGN: TOM WILSON

Self-organized complementary honeycomb structures in the density of cold atoms (blue) and hexagonal peaks in a light field (purple/green matrix) resulting from an optomechanical instability: atoms tell the light how to bend, and the light tells the atoms how to move.

Letter p321

IMAGE: P. GOMES & R. KAISER

COVER DESIGN: TOM WILSON

Attosecond technology could be used to advance electronics to its ultimate speed limit — optical frequencies. The image is an artist’s view of the basic building block of future lightwave electronics, a nanoscale dielectric switching circuit driven by visible to infrared light. The white beam transports a wideband lightwave into the circuit. Each high-intensity spike of the oscillating electric field causes the initially insulating chip to become conducting for ~10-15 s. The conductivity is thus repeatedly turned on and off by the oscillating electric field. An electric current (the green spheres are electrons) flows through the chip during the conducting periods and is blocked during the insulating periods. The resulting sequence of current bursts leaving the chip represents electronic signal modulation at light (that is, near-petahertz) frequencies.

Review p205

IMAGE: CHRISTIAN HACKENBERGER, LUDWIG-MAXIMILIANS UNIVERSITäT

COVER DESIGN: TOM WILSON

A silicon-on-insulator device that combines two four-wave-mixing sources in an interferometer with a reconfigurable phase shifter is presented. It does not require any external photon sources, and represents a first step towards realizing fully integrated quantum technologies.

Letter p104; Interview p160

IMAGE: YUE ZHANG, JOSH SILVERSTONE, DAMIEN BONNEAU AND MARK THOMPSON

COVER DESIGN: TOM WILSON

The chiral crystal structure of a three-dimensional spin-crossover assembly based on an ironoctacyanoniobate, Fe2[Nb(CN)8](4-bromopyridine)8·2H2O, with p-polarized fundamental input light (red wave) and s-polarized output second-harmonic light (green wave). This assembly exhibits photoswitching of magnetization-induced second-harmonic generation. The polarization plane of the output second-harmonic light can be optically switched by 90°.

Article p65; Interview p80

IMAGE: SHIN-ICHI OHKOSHI

COVER DESIGN: TOM WILSON