Fast Photon-Mediated Entanglement of Continuously Cooled Trapped Ions for Quantum Networking.

We entangle two cotrapped atomic barium ion qubits by collecting single visible photons from each ion through in vacuo 0.8 NA objectives, interfering them through an integrated fiber beam splitter and detecting them in coincidence. This projects the qubits into an entangled Bell state with an observed fidelity lower bound of F>94%.

Ion trap with in-vacuum high numerical aperture imaging for a dual-species modular quantum computer.

Photonic interconnects between quantum systems will play a central role in both scalable quantum computing and quantum networking. Entanglement of remote qubits via photons has been demonstrated in many platforms; however, improving the rate of entanglement generation will be instrumental for integrating photonic links into modular quantum computers. We present an ion trap system that has the highest reported free-space photon collection efficiency for quantum networking.

Author Correction: Robust topologically protected transport in photonic crystals at telecommunication wavelengths.

In the version of this Letter originally published, Fig. 5g in the Supplementary Information was missing the scale bar. This has now been corrected.

Reconfiguring structured light beams using nonlinear metasurfaces.

Ultra-compact, low-loss, fast, and reconfigurable optical components, enabling manipulation of light by light, could open numerous opportunities for controlling light on the nanoscale. Nanostructured all-dielectric metasurfaces have been shown to enable extensive control of amplitude and phase of light in the linear optical regime. Among other functionalities, they offer unique opportunities for shaping the wave front of light to introduce the orbital angular momentum (OAM) to a beam.

Robust topologically protected transport in photonic crystals at telecommunication wavelengths.

Photonic topological insulators offer the possibility to eliminate backscattering losses and improve the efficiency of optical communication systems. Despite considerable efforts, a direct experimental demonstration of theoretically predicted robust, lossless energy transport in topological insulators operating at near-infrared frequencies is still missing. Here, we combine the properties of a planar silicon photonic crystal and the concept of topological protection to design, fabricate and characterize an optical topological insulator that exhibits the valley Hall effect.

High-Efficiency All-Dielectric Metasurfaces for Ultracompact Beam Manipulation in Transmission Mode.

Metasurfaces are two-dimensional structures enabling complete control on light amplitude, phase, and polarization. Unlike plasmonic metasurfaces, silicon structures facilitate high transmission, low losses, and compatibility with existing semiconductor technologies. We experimentally demonstrate two examples of high-efficiency polarization-sensitive dielectric metasurfaces with 2π phase control in transmission mode (45% transmission efficiency for the vortex converter and 36% transmission efficiency for the beam steering device) at telecommunication wavelengths.

Experimental demonstration of a non-resonant hyperlens in the visible spectral range.

A metamaterial hyperlens offers a solution to overcome the diffraction limit by transforming evanescent waves responsible for imaging subwavelength features of an object into propagating waves. However, the first realizations of optical hyperlenses were limited by significant resonance-induced losses. Here we report the experimental demonstration of a non-resonant waveguide-coupled hyperlens operating in the visible wavelength range.

Twisted light in a nonlinear mirror.

Opposite directionality of the Poynting vector and the wave vector, an inherent property of negative index metamaterials (NIMs), was predicted to enable backward phase-matching condition for a second harmonic generation (SHG) process. As a result, such a nonlinear negative index slab acts as a nonlinear mirror. In this Letter, we predict that SHG with structured light carrying orbital angular momentum (OAM) and propagating in NIMs results in a possibility of generating a backward propagating beam with simultaneously doubled frequency, OAM, and reversed rotation direction of the wavefront.

Negative group velocity and three-wave mixing in dielectric crystals.

We investigate extraordinary features of optical parametric amplification of Stokes electromagnetic waves that originate from the three-wave mixing of a backward phonon wave with negative group velocity and two ordinary electromagnetic waves. Such properties were earlier shown to exist only in plasmonic negative-index metamaterials that are very challenging to fabricate. Nonlinear optical photonic devices with properties similar to those predicted for negative-index metamaterials are proposed.

[Results of treating strangulated external abdominal hernias].

The analysis of 423 case records of the patients operated upon for incarcerated external abdominal hernia within the 10 years' period (1966--1975) has been carried out. The patients are classified with the reference to the severity of the disease, duration of incarceration, diagnostic errors, clinical course, hospitalization period, type of a surgical intervention, outcome of the treatment and complications.

[Changes in the acetylcholine concentration and acetylcholinesterase activity in the thyroid gland tissues and in serum cholinesterase activity in goiter].

A study was made of acetylcholine concentration and of the acetylcholinesterase activity in the thyroid gland tissue, as well as of the serum cholinesterase activity in the toxic goiter. This disease was accompanied by an elevation of the acetylcholine concentration and a fall of the eacetylcholinesterase activity. As to serum cholinesterase--it changed but little in this disease.

[Combined method of rectopexy in rectal prolapse with the use of skin autoimplants].

During 1964-1973 twenty six patients were operated upon for grave rectal prolapse (6 patients after 1-2 unsuccessful operations elsewhere). The combined method of rectopexy by means of skin autoimplants after the technic suggested by B.A.