Laser emits multi-wavelength light
Semiconductor lasers are usually monocromatic because the electrons stored in energy bands do not emit any photons unless they move out of the semiconductor’s conduction band. Federico Capasso a...
Microlasers get even smaller
Attempts to scale down current laser designs have been made before, but the devices were not efficient enough for real applications. Now a group of researchers from Darmstadt University of Technology,...
Achieving optical super resolution
When light hits an object, diffraction causes the beam to spread over an area that depends on the aperture of the lens. The phase filters make this area smaller but also cause a reduction in the beam ...
Lasers, chaos, and bow-ties
Laser technology has come a long way since the 1960s. The very earliest lasers, such as ruby and helium-neon devices, were formidable contraptions. They relied on dilute active media with discrete ene...
Deuterium ‘shocked’ into metallic state
Gilbert Collins and colleagues used the NOVA laser at the Lawrence Livermore National Laboratory in California to carry out the experiments (Science 281 1178). The deuterium was placed in a small copp...
Making light work of gravity gradients
The interferometer was built by Mark Kasevich and colleagues at Yale University in the US and used individual atoms, rather than macroscopic man-made objects, to measure the gradient. By observing the...
Holographic storage sees light
Their technique works by using a process called two-colour holography. One wavelength of light records information on the crystal and another is used to read the data. Their method fires two light sou...
Light makes insulator conduct
The researchers cooled the manganese oxide compound (Pr0.7Ca0.3MnO3) to below 200 K in a zero magnetic field. At this temperature the electrons drop into a low energy state, which minimizes their natu...
Blood tests without needles
Recognising blood cells presents a big challenge for automated counting systems. As blood flows through veins, the cells are deformed in the direction of blood flow. Blood also contains a lot of other...
Fibre gives X-ray generation a boost
The efficiency with which light of one frequency is converted into a higher frequency in a nonlinear material increases when both frequencies travel through the material with the same phase velocity. ...
