Articles in 2012

Experimental demonstration of Anderson localization in three dimensions is a challenging task. Here researchers present a direct and absorption-independent measure of the localization length and evidence for a localization transition in three dimensions.

Researchers report the entanglement-enhanced measurement of a delicate material system, in which they non-destructively probe an ⁸⁵Rb atomic spin ensemble by near-resonant Faraday rotation. They use narrowband, atom-resonant ‘NOON’ states to beat the standard quantum limit of sensitivity by more than five standard deviations, both on a per-photon and a per-damage basis.

Researchers focus 10 keV X-ray free-electron laser radiation to an area of 0.95 µm × 1.20 µm with near-100%-efficiency using reflective optics. This approach increases the fluence by a factor of 40,000 and provides a power density of 6 × 10¹⁷ W cm⁻².

Scientists report that the photovoltaic effect and a photo-induced bolometric effect, rather than thermoelectric effects, dominate the photoresponse during a classic photoconductivity experiment in biased graphene. The findings shed light on the hot-electron-driven photoresponse in graphene and its energy loss pathway via phonons.

Researchers demonstrate that Bell's measure — a commonly used test of quantum nonlocality — can be used in classical optical schemes to separate incoherence associated with statistical fluctuations from incoherence based on correlation. This technique may be useful for quantum information applications such as classical optical coherence theory and optical signal processing.

Magnetic effects are fundamentally weak at optical frequencies. Now, by applying inhomogeneous strain in photonic band structures of a honeycomb lattice of waveguides, scientists show experimentally and theoretically that it is possible to induce a pseudomagnetic field at optical frequencies. The field yields 'photonic Landau levels', which suggests the possibility of achieving greater field enhancements and slow-light effects in aperiodic photonic crystal structures than those available in periodic structures.

Random lasing in the presence of nonlinearities and disordered gain media is still poorly understood. Researchers now present a semiclassical theory for multimode random lasing in the strongly scattering regime. They show that Anderson localization — a wave-interference effect — is not affected by the presence of nonlinearities, but instead suppresses interactions between simultaneously lasing modes.

Researchers demonstrate large cross-phase shifts of 0.3 mrad per photon in a single pass through room-temperature Rb atoms confined to a hollow-core photonic bandgap fibre. The response time of less than 5 ns indicates that phase modulation bandwidths greater than 50 MHz are possible with a highly sensitive atomic-vapour-based scheme.

Coherent control is a powerful tool for controlling light–matter interactions in time and frequency. Now, scientists show that counter-propagating broadband pulses can be used to generate fully controlled spatial excitation patterns. This spatial control approach also reduces decoherence, providing a high-frequency resolution similar to that of an optical frequency comb.

Researchers at Osaka University in Japan have developed a hyperspectral stimulated Raman microscope that can image the chemical bonds in living tissues at video rates.