A room-sized ring laser interferometer in Germany can track changes in the length of Earth’s day with millisecond precision.

See Schreiber et al. and Ciminelli and Brunetti

Photoacoustic vibrational spectroscopy is shown to be able to detect and fingerprint single particles deposited on the surface of an optical microresonator. The approach, demonstrated with single cells and polystyrene particles, offers new opportunities for biosensing and optomechanics.

See Tang et al.

Nanoplasmonic antennas enable real-time monitoring of the release of enzymes from bacteria (green rods) and the dynamics of the behaviour.

See Lu et al.

The cover shows a wide-field, super-resolution image of a collection of cells captured by a new variant of optical fluctuation imaging that makes use of autocorrelation and two-step deconvolution. The high-throughput approach needs just 20 frames to bring a two-fold improvement in axial and lateral resolution. In ten minutes it can capture a 2 mm × 1.4 mm field-of-view image containing thousands of cells, with a resolution of 128 nm.

See Zhao et al.

Artistic image of a reconfigurable photonic processor, which is ‘programmed’ via a carefully designed spatial pattern of pump light that illuminates an active InGaAsP chip from above. The chip features optical input and output ports at either side and dynamic and spatial control of this pump light distribution allows the chip’s imaginary index to be programmed so that the chip acts as an arbitrary matrix processor and can perform machine learning tasks such as vowel recognition.

See Wu et al.

Artistic impression of a very-large-scale integrated quantum graph photonic chip. Complex-weighted graphs with different topologies are realized to achieve various quantum information tasks such as multiphoton multidimensional entanglement and fully programmable Gaussian Boson sampling.

See Bao et al.

The Pacific cleaner shrimp’s brilliant white stripe is revealed to be due to multiple scattering from birefringent protein nanospheres. The finding could yield new approaches for fabricating ultrathin white coatings.

See Lemcoff et al. and Wiersma

Artistic images of green perovskite light-emitting diode (PeLED) pixels integrated onto a thin-film-transistor backplane to create high-definition active matrix displays. This work represents a start point to bringing PeLEDs from the laboratory towards commercial displays.

See Li et al.

An artistic representation of a resonant plasmonic micro-racetrack modulator that translates an input voltage signal to an output optical signal, with high-speed, energy-efficient operation. The device is based on silicon photonic waveguides and an active, plasmonic phase shifter between metal electrodes, and is thermally stable.

See Eppenberger et al.

The image shows a lightning strike being guided by a terawatt laser beam that is projected into the sky, near a tower on top of a mountain in Switzerland. The results are the first successful field trial of laser guidance of lightning outside of the lab.

See Houard et al. and Arnold et al.

Artistic image of hard X-rays being emitted from a network of carbon nanotubes that have been illuminated with intense, femtosecond pulses from a petawatt laser. The approach may yield a new source of X-rays with applications in imaging and materials science.

See Shou et al. and Macchi and Pegoraro

This issue of Nature Photonics features a focus on metasurfaces, flat ultrathin components formed from arrays of subwavelength structures for manipulating electromagnetic waves. The cover image is an artist’s impression of a multi-layered metalens designed for achromatic operation in the visible range. The lens comprises three frequency-selective metasurfaces, engineered to focus red, green, and blue light to the same white focal spot. The entire lens is less than half a micrometre thick. The lens uses 2D metasurfaces in a multi-layered design for obtaining integrated ultra-flat multispectral and multifunctional optics.

See Neshev and Miroshnichenko