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X-ray scattering experiments indicate that the molecular orientation at the interfaces of bulk heterojunction organic solar cells influences the cells’ fill factor and short-circuit current.
Violation of the classical bound of the three-particle Mermin inequality by nine standard deviations is experimentally demonstrated by closing both the locality and freedom-of-choice loopholes; only the fair-sampling assumption is required. To achieve this, a light source for producing entangled multiphoton states and measurement technologies for precise timing and efficient detection were developed.
A simple experiment enables simultaneous long-range spatial structuring of a cold atomic cloud and an optical pump field, with an adjustable length scale.
Plasma channels induced in air by femtosecond-laser filamentation are useful for many applications, including attosecond physics and spectroscopy and remote sensing. By appropriately employing a surrounding auxiliary dressing beam to continuously supply energy to the filament, the natural range of the plasma column has been extended by at least one order of magnitude.
An optical memory is demonstrated in a kagome photonic crystal fibre whose 26-μm-diameter hollow core is loaded with cesium atoms. Gigahertz-bandwidth light is stored using a far-detuned Raman interaction. It has a memory efficiency is 27 ± 1% and a signal-to-noise ratio of 2.6:1 — the highest at the single-photon level of any memory at room temperature.
Emulation of noiseless linear amplification of quantum states of light is demonstrated by post-selection of measurement data obtained by heterodyne detection. Using this protocol, Einstein–Podolsky–Rosen entanglement is recovered after its degradation by transmission loss. This protocol is applicable to other quantum communication protocols, including teleportation and remote state preparation.
By exploiting a self-bending point spread function based on Airy beams, a three-dimensional super-resolution fluorescence imaging is realized. A three-dimensional localization precision in the range 10–15 nm was obtained at an imaging depth of 3 µm from ∼2,000 photons per localization.
Blue organic light-emitting diodes that harness thermally activated delayed fluorescence are realized with an external quantum efficiency of 19.5% and reduced roll-off at high luminance.
Researchers demonstrate unequivocal quantum interference between plasmons in a Hong–Ou–Mandel experiment. The results may be important for quantum information applications of plasmonics.
An integrated nanoscale light-emitting diode is used as an electrically driven optical source for exciting two-dimensionally localized gap plasmon waveguides with a 0.016λ2 cross-sectional area. Electrically driven subwavelength optical nanocircuits for routing, splitting and directional coupling are demonstrated in compact and relatively low-loss gap plasmon waveguide structures.
Polarization-entangled photon pairs are generated from an In(Ga)As quantum dot by setting the pump intensity such that the inversion of the quantum dot from the ground to the biexcitonic state is the most probable transition. On-demand generation is demonstrated with an ultrahigh purity, a high entanglement fidelity and high two-photon-interference non-post-selective visibilities.
The first observation of a third-order process induced by an X-ray beam from a free-electron laser is realized in germanium using a 5.6-keV X-ray beam. Two-photon absorption is confirmed, suggesting that X-ray analogues of other third-order nonlinear processes may be available for exploitation in X-ray experiments.
A photodiode-based logic device employing scalable heterojunctions of carbon nanotubes and silicon whose output currents can be manipulated by both optical and electrical inputs is developed. Bidirectional phototransistors and novel clock-triggerable logic elements, such as a mixed optoelectronic AND gate, a 2-Bit optoelectronic ADDER/OR gate and a 4-Bit optoelectronic D/A converter, are also demonstrated.
A phase modulator that is only 29 µm long and operates at 65 GHz is demonstrated using plasmonics and the Pockels effect in a nonlinear polymer. The device operates across a 120-nm-wide wavelength range centred on 1,550 nm and at temperatures up to 85 °C.
A quantum memory for orbital angular momentum qubits is demonstrated in the single-photon regime. It is based on cold cesium atoms and the dynamic electromagnetically induced transparency protocol. Retrieved states were analysed by quantum tomography, and fidelities after readout of over 92% were obtained, confirming the quantum functionality of the storage process.
An optical-frequency comb-based scheme is demonstrated that transfers a 4.5 × 10−16 fractional frequency stability from a 1,062-nm-wavelength laser to a 1,542-nm-wavelength laser. Transfer is also reported down to 4 × 10−18 at 1 s, which is one order of magnitude below that of previously reported work with comparable systems.
Mid-infrared spectroscopy with nanometre spatial resolution is highly desired for materials and life sciences applications. A nanoscale mid-infrared spectrometer is demonstrated that detects mechanical forces exerted by molecules on an atomic force microscope tip upon light excitation. It operates under ambient conditions with a high sensitivity and a spatial resolution of better than 25 nm.
A universal pseudo-cooling method based on a Maxwell-demon-like swapping sequence is proposed. A controlled Hamiltonian gate is used to identify lower energy states of the system and to drive the system to those states. An experimental implementation using a quantum optical network exhibits a fidelity higher than 0.978.
A dual-wavelength fibre laser source has been developed for stimulated Raman scattering microscopy. It is precisely tunable over the entire high-wavenumber region of Raman spectra, where most stimulated Raman scattering imaging is performed. Imaging speeds of up to 1 frame s−1 with shot-noise-limited sensitivity were achieved.
Terahertz waveforms with peak fields of 72 MV cm−1 and a central frequency of 30 THz drive interband polarization in bulk GaSe off-resonantly and accelerate excited electron–hole pairs, inducing dynamical Bloch oscillations. This results in the emission of phase-stable, high-harmonic transients over the whole frequency range of 0.1–675 THz.
