Articles in 2009

Based on a far-field fluorescence-based optical super-resolution scheme – stimulated emission depletion microscopy – scientists resolve densely packed individual fluorescent colour centres inside crystals with a far-field spatial resolution of 5.8 nm without photobleaching. The approach will support future studies of solid-state single-photon sources and quantum optics.

Controlling the orientation of the constituent parts of a metamaterial enables the creation of a new family of optical stereoisomer materials that have an electromagnetic response that can be carefully tailored.

The effect of a tiny gap in a metal substrate on incident terahertz radiation in the regime where the gap's dimensions are smaller than the metal's skin-depth are investigated. The results and theoretical analysis show that the gap acts as a capacitor charged by light-induced currents, and dramatically enhances the local electric field.

Using a single layer of electrically controlled metamaterial, researchers have achieved active control of the phase of terahertz waves and demonstrated high-speed broadband modulation.

A system based on a highly nonlinear planar chalcogenide waveguide is demonstrated to be able to perform radio-frequency spectral measurements with a terahertz bandwidth. High bit-rate tests show that the chip-based system is potentially useful for ultrafast signal processing.

Nature Photonics spoke to Zongfu Yu and Shanhui Fan from Stanford University about their proposed 'one-way valve for light' that suits integration on a photonic silicon chip.

Photovoltaics and LED lighting look set to ride out the economic downturn, but a spate of consolidation in other sectors is likely as markets decline in 2009.

Accurate and efficient testing is essential for ensuring the quality and safety of the food we eat. Whereas most analysis methods are destructive, Duncan Graham-Rowe reports that optical techniques are not only non-invasive but in some cases can also assess nutritional content.

Practical low-loss metamaterials at optical frequencies may soon be realized thanks to optical parametric amplification that uses backwards propagation of a signal beam in negative-index metamaterials. Surprisingly, increasing losses at the idler frequency leads to broadband transparency or amplification at the signal frequency.

Storing a light pulse in a vapour is by now a standard laboratory technique. For such optical memory to become truly practical, however, the fidelity of the technique has to be improved. Combining light storage with nonlinear wave mixing may offer a way forwards.

By using an optical frequency comb as a light source for Fourier transform spectroscopy, scientists show that well-resolved absorption and dispersion spectra can be recorded simultaneously, providing sensitive detection of multiple molecular species over a broad spectral window.

The emergence of convenient sources of broadband light spanning the visible and near-infrared is proving increasingly useful for applications involving spectroscopy, imaging and metrology, reports Neil Savage.

While many areas of photonics are being hit hard by the global recession and credit-crunch, others such as solar energy generation and solid-state lighting seem to be continuing to flourish.

A spectral decomposition of the fluorescence emission from labelled receptors within cells, together with a simple but accurate data analysis of their mutual Förster resonant energy transfer, can provide high-resolution real-time imaging of the fate of intracellular proteins.

For integrated photonics to take off, light signals zooming around optical chips must be successfully isolated from one another. Scientists at Stanford University have now designed a miniature one-way valve for light that uses photonic transitions and is potentially compatible with silicon-chip CMOS fabrication processes.

The use of fluorescent tagging and nanoscale waveguides looks set to make real-time DNA sequencing a realistic proposition. Commercial devices based on nanophotonics are expected in 2010.

The year 2009 marks the tenth anniversary of the first report of white-light supercontinuum generation in photonic crystal fibre. This result had a tremendous impact on the field of nonlinear fibre optics and continues to open up new horizons in photonic science. Here we provide a concise and critical summary of the current state of nonlinear optics in photonic crystal fibre, identifying some of the most important and interesting recent developments in the field. We also discuss several emerging research directions and point out links with other areas of physics that are now becoming apparent.

By using an optical frequency comb as the light source for Fourier transform spectroscopy, scientists show that well-resolved broadband absorption and dispersion spectra can be recorded in a single experiment, providing sensitive detection of multiple molecular species over a broad spectral window.