Smartphones as thin as a credit card?
Sounds unlikely right now, as most smartphones are still a few
millimeters thick (for example, the iPhone 5 is 7.6 mm thick). However,
scientists say that over 1,500 of these lenses can fit within the
thickness of a human hair (25.4 micrometers thick, around 0.0254 mm), which makes you wonder how much thinner smartphones will be getting in the years ahead.
The lenses used to focus light in eyeglasses, microscopes and other
products use the same basic technology dating back to the late 13th
century, when spectacles were invented in Europe. However, existing
lenses are not thin or flat enough to remove the various distortions
that prevent the creation of the sharpest image possible. Solutions to
correct those distortions are often complicated, such as adding multiple
lenses that increase the weight and space that a device takes up.
Federico Capasso and his colleagues sought to make a superthin and flat
lens that would solve this problem, which could drastically reduce the
weight and thickness of devices with lenses.
This new superthin lens has a resolving power that actually
approaches the theoretical limits set by the laws of optics. The lens
surface is patterned with tiny metallic stripes which bend light
differently as one moves away from the center, causing the beam to
sharply focus without distorting the images. The current version of the
lens works at a specific design wavelength, but the scientists say it
can be redesigned for use with broad-band light.
Although this is just in the experimental stages, it is interesting
to keep tabs on, especially as smartphones and tablets compete to get
thinner and thinner than their previous editions.
