"We have fabricated the first negative index concave lens at telecommunications frequencies and with an ultrashort focus," Srinivas Sridhar, a professor at Northeastern University, told optics.org.

The lens has an aperture of 80 micrometers - roughly the size of the cross-section of human hair - and a focal length of 60 micrometers. Lenses are the key part of imaging systems such as ...

That may not seem too disturbing, but the lens is concave and works in exactly the opposite manner of how such a lens should. Metamaterials have an air of magic about them. The elements they’re ...

These hyperchromatic lenses, consisting of a positive diffractive lens and a tunable concave lens, are designed to have a large longitudinal chromatic dispersion and thus axially separate the ...