News & Views in 2008

A strongly nonlinear photonic crystal with a wavelength-tunable bandgap could provide the solution to realizing all-optical switches for signal processing.

Thin-membrane mirrors based on subwavelength gratings are transforming the performance of tunable VCSELs.

Subwavelength holes in metal films are well known to offer extraordinary-light-transmission properties. Now a group of scientists in France have exploited such nanoholes to sort photons by colour.

By structuring the surface of a metal with an array of holes, photonics researchers show that it is possible to tightly confine terahertz surface waves, reducing their decay length into air by two orders of magnitude. The results could lead to new approaches to waveguiding.

The demonstration of a laboratory-scale, fully coherent extreme-UV laser opens up a whole plethora of applications in ultrashort-wavelength imaging, microscopy and the probing of matter.

Non-reciprocal optical phenomena — effects that depend on the direction of light propagation — are rare. Researchers have now observed non-reciprocal material modification when moving a beam of ultrashort light pulses through a lithium niobate crystal.

Diffuse scattering can prevent high-resolution imaging in thick biological media. Researchers have now shown that such scattering can be completely cancelled by optical phase conjugation, opening the path to a new generation of medical imaging techniques.

An optoelectronic method for sorting nanowires of different compositions and assembling them into reconfigurable arrays could be important for creating future nanodevices.

Chains of coupled resonators are capable of dramatically slowing the speed of light. When all the resonators are identical light can, in principle, be stopped altogether. However, disorder causes light to move at a finite speed and to be localized over a few resonators.

Solar cells take advantage of our most abundant source of energy, the Sun. A technique that improves the conversion of photons to electrons could potentially lead to a dramatic improvement in device efficiency.

Researchers at Harvard Medical School have developed a highly sensitive microscope that can image the mechanical properties of living tissues.

Defect engineering is crucial for realizing all-optical integrated circuits from self-assembled photonic crystals. A two-photon polymerization strategy paves the way towards incorporation of arbitrary defects in silicon inverse opal photonic crystals.

The regeneration of weak and distorted optical signals is vital in long-haul optical communication systems. Now scientists at Cornell University have developed an all-optical scheme that performs the task and is small enough to fit on a chip.

A re-examination of firefly bioluminescence has revealed that the efficiency of light generation in fireflies is actually less than half the widely accepted value. The study also casts doubts over the mechanism that determines the colour of the emission.