Less than a decade after the end of the Civil War, in 1873, Ernst Abbe published an equation showing how microscope resolution is limited by the wavelength of the light. For the greater part of the 20th century scientists believed they would never be able to observe things with optical microscopes smaller than roughly half the wavelength of light. A principle set in stone for over one hundred years without challenge.
Stephan Hell was convinced that there had to be a way of circumventing Abbe’s diffraction limit. While exploring other topics, he read the words stimulated emission in a book on quantum optics and new line of thinking took shape in his mind: “At that moment, it dawned on me. I had finally found a concrete concept to pursue – a real thread.”
He devised a kind of nano-flashlight that could sweep along a sample, a nanometre at a time. Today, all nanoscopy concepts utilize a transition between two states which is operated as a fluorescence switch. In one state the molecule is fluorescent in the other state it is non-fluorescent; between both states can be switched via (nano-flashlight) light of a characteristic wavelength enabling higher resolution measurements.
Successful design tenants illustrated in this example:
- Strong belief a solution could be devised, and that the search was worthwhile
- Borrowed a concept from another field
- The importance of diversity of ideas and thinking
- Pursued his idea with intensity
- Collaboration with other subject matter experts
His confidence and persistence paid off: he was one of three recipients of the 2014 Noble Prize for chemistry.