Articles

Researchers experimentally demonstrate that light propagating through a path-averaged zero-index dielectric medium can have zero phase delay, despite a non-zero physical path length. The medium is a superlattice consisting of layers of negative-refractive-index dielectric photonic crystals and positive-refractive-index homogeneous dielectric media.

Scientists experimentally demonstrate an optical-fibre-based non-degenerate phase-sensitive amplifier link that offers broadband amplification, signal modulation-format independence and lower noise than links based on conventional erbium-doped fibre amplifiers.

Scientists show that spatiotemporal focusing and compression of non-Fourier-limited pulses through scattering media can be achieved by manipulating only the spatial degrees of freedom of the incident wavefront. This technique is potentially attractive for optical manipulation and nonlinear imaging in scattering media.

Researchers demonstrate the real-time generation and fast Fourier transformation of 10.8 Tbit s⁻¹ and 26 Tbit s⁻¹ line-rate optical frequency-division multiplexed signals, using an all-optical fast Fourier transform scheme based on cascaded delay interferometers and a time gate.

Researchers demonstrate a terahertz quantum cascade laser operating in a regime of active mode-locking by modulating its bias current with a radiofrequency synthesizer. This technique allows coherent sampling of the terahertz electric field as well as control over the laser's carrier–envelope phase shift.

Scientists describe a size-selective quantum dot patterning technique that involves kinetically controlling the nanotransfer process without a solvent. The resulting printed quantum dot films exhibit excellent morphology and a well-ordered quantum dot structure. This technique allows fabrication of a 4-inch (or larger) thin-film transistor display with high colour purity and extremely high resolution.

Based on a CMOS-compatible growth process, researchers successfully demonstrate the bottom-up integration of InGaAs nanopillar lasers onto silicon chips. The resulting nanolaser offers tiny footprints and scalability, making it particularly suited to high-density optoelectronics.

Spectral modulation of a broadband pump beam allows sensitive and specific molecular imaging based on stimulated Raman scattering. Measurements of cholesterol, protein, and stearic and oleic acid are reported.

Laser spectroscopy based on the nonlinear photothermal and photoacoustic spectral resonances of nanoparticles is demonstrated. This approach will be potentially useful for applications such as multispectral imaging, multicolour cytometry, and the study of laser–nanoparticle interactions at a resolution beyond the spectral limit.

Researchers propose a new type of multiphoton entangled state and demonstrate its working principles of measurement-based quantum computation in correlation space. With four- and six-qubit states, they realize a universal set of single-qubit rotations, two-qubit entangling gates and further Deutsch's algorithm.

Researchers use a nonlinear coherent imaging technique to demonstrate distant coherent coupling between excitons in quantum wells. The long-range nature of the coupling is attributed to the existence of spatially extended exciton states up to the micrometre range.

Scientists demonstrate an optical analogue of aerodynamic lift, in which an airfoil-shaped refractive object can be controlled through the radiation pressure induced by refracted and reflected rays of light.

Researchers demonstrate a probabilistic noiseless linear amplifier based on photon addition and subtraction. The technique enables coherent states to be amplified to the highest levels of effective gain and final-state fidelity, and could become an essential tool for applications in quantum communication and metrology.

Using ∼1-mm-long photonic crystal waveguides, scientists experimentally demonstrate the compression of 3 ps pulses to a minimum duration of 580 fs at a low pulse energy of ∼20 pJ. The approach may pave the way for soliton applications in integrated photonic chips.

Researchers report the generation of isolated sub-160-attosecond pulses that have photon energies of 30 eV, resulting in an on-target pulse energy of a few nanojoules. The availability of attosecond sources with high peak intensities may open new avenues for attosecond pump/probe studies of electronic processes in atomic and molecular physics.

By combining advanced ultrashort-pulse laser technology with scanning tunneling microscopy, scientists demonstrate that they can directly image transient carrier dynamics in nanostructures in real space.

Colour conversion of single photons may allow the advantages of quantum systems operating at different wavelengths to be simultaneously utilized. Researchers demonstrate the colour conversion of triggered single photons from a semiconductor quantum dot between 1.3 µm to 710 nm. The up-converted signal maintains the quantum character of the original light.

A prototype microscope built with self-reconstructing Bessel beams is shown to be able to reduce scattering artifacts as well as increase image quality and penetration depth in three-dimensional inhomogeneous opaque media.

Researchers describe a theoretical mechanism that may ensure high-fidelity entanglement of photons, and thus could be used to construct a practical quantum repeater. The communication rate is shown to be a function of the maximum distance between any two adjacent quantum repeaters, rather than of the entire length of the network.

The effects of interactions on Hanbury Brown and Twiss interferometry are studied by considering the propagation of light in a nonlinear optical medium. The interactions affect the multipath interference, which makes it difficult to extract information about the light source. Nevertheless, the recovery of the disordered information is demonstrated through proper analysis.