Hell had first described STED – which cracks the diffraction limit that has for so long bounded optical microscopy – in a brief two-and-a-half page mathematical treatise six years earlier. "I had a very hard time to convince people it would work," Hell recalls. The idea of a "diffraction barrier," a physical constraint on light microscopy resolution, was simply too well ingrained.
Following his 2000 article, though, researchers started paying attention; the publication has racked up some 310 citations, according to the ISI Web of Knowledge. It also attracted the notice of microscopy manufacturer Leica Microsystems who licensed STED technology in 2001 and began converting it into a viable commercial system. It would take some five years. Along the way, Leica Microsystem's engineers, physicists, and microscopists, aided by members of Hell's own lab, would have to rethink most of the original benchtop design.