Volume 7 Issue 4, April 2013

Could massive arrays of thousands of fibre lasers be the driving force behind next-generation particle accelerators? The International Coherent Amplification Network project believes so and is currently performing a feasibility study.

Despite great efforts to develop silicon-based optoelectronic devices, efficient photon emission from silicon still remains an elusive goal. Nanocavities could offer a path towards efficient silicon light emitters through strong optical confinement.

The combination of ultrasound and optics, together with statistics, now permits light focusing and imaging deep inside strongly scattering media at the optical diffraction limit.

The isolated symmetry points of photonic graphene are unstable in three dimensions. Researchers have now proposed topologically robust points by using minimal surfaces and employing symmetry-breaking ideas from quantum field theory.

A new femtosecond frequency comb scheme is capable of generating microwave signals at a noise level below the shot noise of light.

Experiments with a quantum simulator made from an integrated optical circuit reveal that bosons and fermions react to disorder in different ways, experiencing different strengths of Anderson localization.

By combining the techniques of temporal focusing and generalized phase contrast researchers are able to preserve the shape of spatial patterns of light deep inside scattering brain slices. This approach is shown to photoactivate the light-sensitive protein channelrhodopsin-2 with single-cell precision and millisecond temporal resolution.

Researcher reports data transmission in 37 × 40 Gbit s⁻¹ channels at 99.7% of the speed of light in vacuum in a fundamentally improved hollow-core photonic bandgap fibre with a record low loss of 3.5 dB km⁻¹ and a wide bandwidth of 160 nm.

Researchers obtain bright visible light emission from silicon coupled with plasmon nanocavities due to non-thermal carrier recombination. The team reports an enhanced emission quantum efficiency and the concept is promising for developing monolithically integrated light sources on conventional microchips.

Shot noise originates from the discrete nature of optical field detection. By exploiting correlations in the shot-noise spectrum of optical pulse trains, scientists improve shot-noise-limited optical pulse timing measurements by several orders of magnitude. A photodetected pulse train timing noise floor at an unprecedented 25 zs Hz^−1/2 is reported.

Materials exhibiting three-dimensional (3D) linear dispersion relations between frequency and wavevector are expected to display a wide range of interesting phenomena. 3D linear point degeneracies between two bands (“Weyl points”) have yet to be observed. Based on analytical and numerical analysis, researchers predict Weyl point formation in 3D photonic crystals.

Scientists introduce an approach, time reversal of variance-encoded light (TROVE), that can demix spatial modes within an ultrasound focus inside scattering media, breaking the resolution barrier imposed by the ultrasound. Optical focusing and imaging with diffuse light at a speckle-scale lateral resolution of ∼5 µm is achieved.

The light concentrating properties of single p-i-n GaAs nanowires are shown to result in far greater photocurrent densities than expected under one sun illumination. The results suggest that such cells could in principle operate with power conversion efficiencies beyond the Shockley–Queisser limit.

Researchers demonstrate quantum teleportation of six general states using an entangled-light-emitting diode consisting of an InAs quantum dot. The emission wavelength of quantum dots is readily tunable using electric fields. The average teleportation fidelity of 0.704±0.016 exceeds the limit possible with classical light, proving the quantum nature of the teleportation.

Researchers report the first direct measurements of the wavefunction and Dirac distributions for polarization states of light. Their implementation determines the general description of the pure state of a qubit. This technique is simple, fast and general, and has an advantage over the conventional approach of performing quantum state tomography.

Researchers observe Anderson localization for pairs of polarization-entangled photons in a discrete quantum walk affected by position-dependent disorder. By exploiting polarization entanglement of photons to simulate different quantum statistics, they experimentally investigate the interplay between the Anderson localization mechanism and the bosonic/fermionic symmetry of the wave function.

Using a long-lived quantum-dot spin qubit coupled to a GaAs-based photonic crystal cavity, researchers demonstrate complete quantum control of an electron spin qubit. By cleverly controlling the charge state of the InAs quantum dot using laser pulses, optical initialization, control and readout of an electron spin are achieved.

Complete quantum control of an electron spin qubit can be achieved using a long-lived quantum-dot spin qubit coupled to a GaAs-based photonic-crystal cavity. Samuel Carter from the Naval Research Laboratory says that this system could be used as a node in a quantum network.