-Scattering lens resolves nanoscale objects-
A new type of lens that exploits strong scattering of laser light is
shown to resolve structures at sub-100 nm resolution. Light scattering
was once thought of as a nuisance in microscopy. However, scattering can
enhance imaging when combined with computer-controlled spatial light
modulators. An opaque layer of scattering material can couple light to
modes that cannot propagate in air, thereby increasing the potential
resolution in a similar way to metamaterial superlenses. Such scattering
layers are very easy to produce but they inconveniently scramble all
optical information into a disordered interference pattern called
speckle. In a scattering lens digital spatial light modulators are used
to unscramble the information and transform the speckle into a clear and
tight focus. In the present work researchers have combined such a lens
with a high-refractive-index material to create a focus that is tighter
than any other lens has made before. They scanned this focus in two
dimensions to image a test object - a collection of gold nanoparticles -
and found a resolution of 97 nm. Because the lens produces a real
scanning focus, in future it can be combined with many other methods
ranging from new metamaterial structures to ultrafast fluorescence
methods, to further enhance resolution.
Figure: left - Reference image of a collection of gold nanoparticles.
Right - same image with the scattering lens. The white scale bar is 300
nm.
