of a metre. The name combines the SI prefix nano- with the parent unit name metre. It

can be written in scientific notation as 1×10−9 m, in engineering notation as 1 E−9 m, and

is simply 1 / 1,000,000,000 m. One nanometre equals ten angstroms.

Use The nanometre is often used to express dimensions

on an atomic scale: the diameter of a helium atom, for example, is about 0.1 nm, and that

of a ribosome is about 20 nm. The nanometre is also commonly used to specify the wavelength

of electromagnetic radiation near the visible part of the spectrum: visible light ranges

from around 400 to 800 nm. The angstrom, which is equal to .1 nanometre, was formerly

used for these purposes. History

The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short –

since it is 1/1000 of a micron, and was often denoted by the symbol mµ or µµ. In 1960,

the U.S. National Bureau of Standards adopted the prefix "nano-" for "a billionth". The

nanometre is often associated with the field of nanotechnology. Since the late 1980s, it

has also been used to describe generations of the manufacturing technology in the semiconductor

industry. References

External links Near-field Mie scattering in optical trap

nanometry Nanoscale Informal Science Network