Volume 8 Issue 5, May 2014

Applying structured illumination microscopy to coherent imaging modalities such as scattering does not yield any additional information beyond that provided by oblique illumination. It thus yields no resolution enhancement over the Abbe diffraction limit, which was derived precisely for that case.

To avoid a 'capacity crunch', future optical networks will need to simultaneously transmit multiple spatial channels. For spatial multiplexing to be practical, the upgrade path from legacy wavelength-division multiplexed systems needs to be smooth and to consider integration-induced crosstalk from the outset.

The realization of an X-ray laser plasma amplifier using a stretched X-ray pulse leads to higher intensity and better quality X-ray laser pulses.

Recent advances in quantum information transfer by photons are reviewed. The theoretical framework for information transfer between nodes of a quantum network is described, and several key experiments for remote atom–atom entanglement mediated by light are illustrated. The prospects for hybrid systems currently in development are also discussed.

With the help of two photonic controlled-NOT gates, a three-logical-qubit concatenated Greenberger–Horne–Zeilinger (C-GHZ) state encoded by a six-photon graph state is experimentally created. Observation of the dynamics of distillability evolving under a collective noisy environment revealed that the C-GHZ state is more robust than the conventional GHZ state.

An optical parametric oscillator in the telecom wavelength range is realized in a diamond system consisting of a ring resonator coupled to a diamond waveguide. Threshold powers as low as 20 mW are measured and up to 20 new wavelengths are generated from a single-frequency pump laser.

Kerr frequency combs are well suited for high-capacity data transmission with phase-sensitive modulation formats. This work demonstrates error-free transmission with data rates of up to 1.44 Tbit s⁻¹, spectral efficiencies of up to 6 bit s⁻¹ Hz⁻¹ and transmission distances of up to 300 km.

The first X-ray-pump–X-ray-probe measurement of the nonlinear response of a plasma amplifier perturbed by a ultrashort soft-X-ray pulse is demonstrated. Two time-delayed 18.9-nm-wavelength pulses were incident on a plasma, and the gain depletion induced by saturated amplification of the pump was measured with a femtosecond resolution.

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.

Stokes-shift-engineered CdSe/CdS quantum dots are used to fabricate luminescent solar concentrators that are tens of centimetres long and do not exhibit reabsorption losses. With efficiencies of over 10% and an effective concentration factor of 4.4, they demonstrate the potential of using Stokes-shift-engineered quantum dots in large-area luminescent solar concentrators.

Through shaping of colloidal particles, optical traps with prescribed force–displacement profiles are generated and are used to design a microscopic constant-force spring capable of delivering a constant piconewton-scale restoring force for displacements of several micrometres. Potential future applications include the imaging of sensitive biological membranes.

Researchers demonstrate a watt-class high-power, single-mode photonic-crystal laser operating continuously at room temperature. A beam quality of M² ≤ 1.1 is achieved.

By exploiting hot-carrier injection, the photodetection capabilities of a semiconductor structure have been extended to wavelengths as long as 55 µm, which is well beyond the usual spectral limits determined by energy levels.

By injecting high-energy charge carriers (dubbed 'hot holes') into a semiconductor, scientists have succeeded in realizing photodetectors capable of detecting ultralong wavelengths. Unil Perera from Georgia State University in the USA explains how the devices work and how they can be improved.