Researchers at Stanford University have reclaimed bragging rights for creating the world's smallest writing, a distinction the varsity first gained in 1985 and lost in 1990.
How small is the writing? Well, the letters in the words are assembled from subatomic sized bits as small as 0.3 nanometres, or roughly one third of a billionth of a metre. The researchers encoded the letters"S" and"U" (as in Stanford University) within the interference patterns formed by quantum electron waves on surface of a sliver of copper.
The wave patterns even project a tiny hologram of the data, which can be viewed with a powerful microscope."We miniaturised their size so drastically that we ended up with the smallest writing in history," said Prof Hari Manoharan, who led the researchers.
In fact, working in a vibration-proof basement lab in the Varian Physics Building, Manoharan and colleagues began their writing project with a scanning tunnelling microscope, a device that not only sees objects at a very small scale but also can be used to move around individual atoms.
They used it to drag single carbon monoxide molecules in a desired pattern on copper chip the size of a fingernail. By altering the arrangement of the molecules, the researchers can create different waveforms, effectively encoding information for later retrieval. To encode and read out the data at unprecedented density, they have devised a new technology, Electronic Quantum Holography.
In a traditional hologram, laser light is shined on a two-dimensional image and a ghostly 3-D object appears. In the new holography, the two-dimensional"molecular holograms" are illuminated not by laser light but by the electrons that are already in the copper in great abundance.
The resulting"electronic object" can be read with the scanning tunnelling microscope, the latest issue of the' Nature Nanotechnology' journal reported