Columbia engineers invent a flat lens that exclusively focuses light of a selected color—it appears entirely transparent until they shine a beam of light with the correct wavelength onto it, when the ...

Harvard researchers have found that silica, long thought to lack the right properties for optical metasurfaces, can sometimes ...

Two parallel optical surfaces often exhibit colorful fringes along the lines of equal thickness because of the interference of light. This simple phenomenon allows one to observe subwavelength ...