Optical vortex

A new optical device developed by engineers at the University of Arizona might allow astronomers to view extrasolar planets directly without the annoying glare of the parent star.

About ten years ago the presence of planets around stars other than our sun was first deduced by the very tiny wobble in the star's spectrum of light imposed by the mutual tug between the star and its satellite. Since then more than 100 extrasolar planets have been detected in this way.

But many astronomers would, however, like to view the planet directly - a difficult thing to do since seeing the planet next to its bright star has been compared to trying to discern, from a hundred meters away, the light of a match held up next to the glare of an automobile's headlight.

Now an approach taken by Grover Swartzlander and his colleagues at the University of Arizona eliminates the star's light by sending it through a special helical-shaped mask, a sort of lens whose geometry resembles that of a spiral staircase turned on its side.