A femtosecond is the SI unit of time equal to 10^-15 of a second.

The word femtosecond is formed by the prefix femto and the unit second. Its symbol is fs.

The waves of visible light oscillate with a period of about 1 femtosecond.

For a list of times on the order of 1-10 femtoseconds, compare 1 E-15 s.

See also

• Femtochemistry.