Volume 17 Issue 1, January 2023

George Palikaras, President and CEO of Meta Materials Inc., discusses the challenges of commercializing metamaterials, learned on the path from a small start-up to a Nasdaq-listed company.

Geoffroy Lerosey, co-founder and CEO/CSO of Greenerwave, shares how tunable metasurfaces may shake up industries from automotive to wireless communications.

Metalenz, a spin-out company from Harvard University founded in 2016, has launched its first metasurface-based product. Nature Photonics spoke with co-founder Federico Capasso about the company and its plans for flat optics.

Using two different designs of superconductor-based detectors, two independent research groups report photon number detection for light pulses with up to 100 photons.

Superconducting nanowire single-photon detectors offer outstanding performance, but the development of large-format imaging arrays is challenging. A new approach based on sectioning a single nanowire enables an eightfold improvement of the spatial resolution and the realization of a 1,024-pixel imager.

The resonance wavelengths of optical Möbius strip microcavities can be continuously tuned via geometric phase manipulation by changing the thickness-to-width ratio of the strip.

Recent advances in optical metalenses are reviewed with a focus on their unique features and applications in the space of optical metasystems.

Robotic and other devices often demand ever more compact and sophisticated sensors. This Review assesses the opportunities for metasurfaces to provide optical functionality solutions for such applications.

Nonlocal effects—in which the optical response of a system at a given spatial point depends on the field in the surrounding space—are reviewed in the context of metasurfaces and flat optics. Nonlocal flat optics may be useful for controlling light in ultra-thin platforms.

Recent developments in reconfigurable metasurfaces are reviewed with a focus on case studies that are promising for commercialization and associated challenges.

A Fourier-transform waveguide spectrometer is demonstrated by using HgTe-quantum-dot-based photoconductors with a spectral response up to a wavelength of 2 μm. The spectral resolution is 50 cm^–1. The total active spectrometer volume is below 100 μm × 100 μm × 100 μm.

A 1,024 pixel superconducting nanowire single-photon imager over a detection area of 403.2 μm × 403.2 μm is demonstrated by introducing an orthogonal time–amplitude-multiplexing method. The spatial resolution and average temporal resolution are 12.6 μm and 67.3 ps, respectively.

Bright upconversion of single nanocrystals is enabled by coupling to a single plasmonic nanocavity mode. An upconversion luminescence enhancement of ~10⁵ was achieved. Single sub-30-nm nanocrystals provided 560 detected photons per second at an excitation intensity of just 0.45 W cm⁻².

Nonlinear absorption of helical light beams offers a new chiroptical detection scheme for both chiral and achiral molecules in liquid phase.

The use of a needle-shaped optical beam improves the depth of field for photoacoustic imaging.

The addition of DDT to the spiro-OMeTAD hole transport material enhances the stability of perovskite solar cells to humidity, heat and illumination stress. Fabricated devices exhibit a champion certified power conversion efficiency of 23.1%. Also, the devices could retain 90% of the initial efficiency after 1,000 h of continuous illumination, 97% under moisture stress for 530 h and 91% under 144 h of heat stress.

A spatially multiplexed detection system of three transition-edge sensors is developed to resolve photon numbers up to 100 in a single laser pulse. Using the detector to measure parity of a coherent state allows for the extraction of quantum random numbers.

Up to 100 photons are resolved by a waveguide-integrated and hybrid spatiotemporal-multiplexed superconducting nanowire single-photon detector array. Using this detector array, photon statistical behaviour for a true thermal and a coherent light source is verified.

The existence of the optical Berry phase in all-dielectric Möbius-strip cavities is experimentally confirmed. In contrast to a predicted sole Berry phase value of π, arbitrary values of the Berry phase upon adiabatic evolution of a linearly or elliptically polarized light wave are obtained.