Volume 4 Issue 6, June 2010

Entangled photon pairs are the key enablers of quantum communications protocols. Researchers at Northwestern University in the USA have now created a convenient and efficient all-fibre source of entangled photon pairs that is promising for standard telecommunications networks.

The experimental demonstration of polariton lasing from an organic optical microcavity is an important step towards the development of practical devices that exploit coupled states of light and matter and operate at room temperature.

The demonstration of a microcavity polariton switch and logic gate that can be controlled by the polarization state of light suggests that a new class of integrated optical devices with highly efficient, ultrafast operation and small footprints may soon be within reach.

An optical technique that allows the coherence of electron spin inside a quantum dot to be manipulated over microsecond timescales may have important applications in quantum information processing.

The aberrations induced by strongly scattering and turbid samples make optical trapping in such media impossible. Now, researchers in Scotland have overcome the problem using in situ aberration correction.

With the recent development of new materials and architectures, solar cell technology is attracting renewed interest from researchers.

By exploiting the Keldysh scaling — universal wavelength scaling laws in strong-field physics — direct temporal characterization of high-harmonics is demonstrated using sum-frequency-generation cross-correlation frequency-resolved optical gating (SFG XFROG).

Evidence that appropriately engineered quantum states outperform both standard and N00N states in the precision of phase estimation — even in the presence of losses and decoherence — is presented. The results show that the strategy for realizing the quantum enhancement of metrology is quite distinct from protecting quantum information encoded in light.

An all-optical spin switch based on exciton–polaritons in a semiconductor microcavity is demonstrated. These results may lead to small and fast spin-based on-chip logic devices.

An ultrafast, all-optical spin echo technique is used to increase the decoherence time of a single quantum dot electron spin from nanoseconds to several microseconds. The ratio of decoherence time to gate time exceeds 10⁵, suggesting strong promise for future photonic quantum information processors and repeater networks.

Polaritons in organic semiconductors are highly stable at room temperature, but so far nonlinear emission from these structures has not been demonstrated. Here, polariton lasing at room temperature in an organic microcavity composed of a melt-grown anthracene single crystal sandwiched between two dielectric mirrors is reported.

Researchers demonstrate free-space quantum teleportation through 16 kilometres of air. The results may pave the way for space-based experiments and global scale quantum communication applications.

Researchers overcome the propagation loss of surface-plasmon polaritons, with this demonstration being the first direct gain measurement of propagating plasmons. Low-loss long-range modes of a metal stripe waveguide are amplified by using optically pumped dye molecules in solution as the gain medium. The mode power gain was measured to be 8.55 dB mm⁻¹.

Distortions in a propagating optical wavefront — known as aberrations — prevent the achievement of a diffraction-limited beam spot. A generic in situ wavefront correction method based on complex modulation is demonstrated, allowing compensation for all aberrations along the whole optical train. The scheme is used for direct trapping through highly turbid and diffusive media, opening up new applications for optical micromanipulation in colloidal and biological physics.

Room-temperature lasing from metallo-dielectric cavities that are smaller than their emission wavelength in all three dimensions is reported. The cavity consists of an aluminium/silica bi-layer shield that surrounds an InGaAsP disk. The gain threshold of the laser is minimized by optimizing the thickness of the silica layer.

The ability to capture and analyse complex, high-speed electronic signals makes the oscilloscope one of the most useful and powerful tools in an engineer's laboratory, reports The Scott Partnership.

Can new types of organic semiconductor lasers offer low-power and coherent integrated sources? Stephen Forrest explains that his team's room-temperature polariton laser gives a reason to be optimistic.