Invisibility
cloaks that are able to steer light around two dimensional objects?
Scientists
have made a hole in time. Brian Handwerk at National Geographic News: Einstein's theories of relativity suggest
that gravity can cause time to slow down. Now scientists have demonstrated a
way to stop time altogether—or at least, to give the appearance of time
stopping by bending light to create a hole in time.
The new
research builds on recent demonstrations of "invisibility cloaks"
that can make objects seem to disappear by bending waves of visible light.
The idea is
that, if light moves around an object instead of striking it, that light
doesn't get scattered and reflected back to an observer, making the object
essentially invisible.
Now Cornell
University scientists have used a similar concept to create a hole in time,
albeit a very short one: The effect lasts around 40 trillionths of a second.
"Imagine
that you could divert light in time—slow it down, speed it up—so that you
create a gap in the light beam in time," said study co-author and Cornell
physicist Alex Gaeta.
"In this
case, any event that occurs at that instant of time won't lead to scattering of
light. It appears as if the event never occurred."
For example,
Gaeta said, think of laser beams crisscrossing a museum display to protect
priceless works of art.
"You have
a laser beam and a detector set up to detect when all of a sudden the beam is
broken and there is no light. So if you pass through that beam, an alarm goes
off," he said. "But what if a
device would perhaps speed up a portion of the beam and slow down another
portion of it so that there is an instant of time with no beam. You could pass
through, and then [on the other side of the event] the device would do the
opposite—speed up the part that had been slowed and slow the part that had been
sped up," he explained. That would
put the beam of light back together, so to speak, so the detector would never
recognize that anything had happened."
Hmm, where do I sign-up?
