Power and Electrical Engineering

The tell-tale signature of most lasers used in everyday applications—from bar-code scanners to pen-size pointers—is a bright red glow. The color is determined by the light’s wavelength, and most lasers emit at only one wavelength. Now a new report published in the current issue of the journal Nature describes a light source measuring only tens of millimeters across that changes color according to temperature.

To make the new laser, Diederik Wiersma and Stefano Cavalieri of the European

A new material helps to make clean fuel from water.

Scientists in Japan have found a more efficient way to extract hydrogen, the ultimate ’green’ fuel, from water. They have developed a material that uses sunlight to break water molecules into their constituent elements of hydrogen and oxygen 1 .

The material is not yet efficient enough to be commercially viable, but its inventors believe that it can be improved. If they are right, hydrogen may soon be on tap

Nerve cells soldered to semiconductors cross computing with neuroscience

Scientists in the United States are soldering nerve cells to semiconductors. Christine Schmidt and colleagues from the University of Texas at Austin use a sliver of protein to connect neurons and tiny crystals of semiconductors called quantum dots 1 .

This cross between biology and electronics could have useful applications, including the manufacture of prosthetics operated directly by a

Solar cells printed like wallpaper.

Solar cells might one day be produced by the roll, as cheaply and easily as wallpaper. Scientists in Arizona are using screen-printing, a technique developed for patterning fabrics, to produce plastic solar cells 1 .

The technique is another step towards the general availability of solar power from flexible devices on plastic sheets or glass panels. The basic materials of a photovoltaic cell are inexpensive, but combining t