Ultrafast plasmonic modulation: Plasmonics converts light into propagating electrical signals. This approach could allow us to shrink optical components to the nanometer scale, far below the hundreds of wavelengths typically set by conventional optics. Ayataet al.fabricated a plasmonic modulator from a single layer of gold using a substrate-independent process. They created a device with a footprint less than the cross-sectional area of a human hair and with modulation rates exceeding 100 GHz, which could provide a flexible platform for future ultrafast plasmonic technology.Science, this issue p.630

The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling – similar to electronics - is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most – a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 10 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspective...

Coherent optical communications provides the largest data transmission capacity with the highest spectral efficiency and therefore has a remarkable potential to satisfy today’s ever-growing bandwidth demands. It relies on so-called in-phase/quadrature (IQ) electro-optic modulators that encode information on both the amplitude and the phase of light. Ideally, such IQ modulators should offer energy-efficient operation and a most compact footprint, which would allow high-density integration and high spatial parallelism. Here, we present compact IQ modulators with an active section occupying a footprint of 4 × 25 µm × 3 µm, fabricated on the silicon platform and operated with sub-1-V driving electronics. The devices exhibit low electrical energy consumptions of only 0.07 fJ bit⁻¹at 50 Gbit s⁻¹, 0.3 fJ bit⁻¹at 200 Gbit s⁻¹, and 2 fJ bit⁻¹at 400 Gbit s⁻¹. Such IQ modulators may pave the way for application of IQ modulators in long-haul and short-haul communications alike.

Switching light on-chip: The development of practical, reconfigurable photonics requires a platform that can be scaled to large circuits and driven by low-voltage complementary metal-oxide semiconductor (CMOS) electronics. Such a platform requires that switching devices possess a compact footprint, low driving voltages, fast switching, low optical losses, and low power consumption. Haffner et al. demonstrate that the combination of opto-electro-mechanical effects with plasmonic devices can provide a platform that meets all the above criteria. The results are promising for developing on-chip integrated optical networks that can be switched by CMOS-level voltages. Science , this issue p. 860