An attosecond (abbreviated as as) is a unit of time in the International System of Units (SI) equal to 10−18 or 1⁄1 000 000 000 000 000 000 (one quintillion) of a second. An attosecond is to a second as a second is to about 31.71 billion years. The attosecond is a newly discovered "slice of time" that is tiny but has various potential applications: it can observe oscillating molecules, the chemical bonds formed by atoms in chemical reactions, and other extremely tiny and extremely fast things.
In 2001, Ferenc Krausz and his team at the Technical University of Vienna fired an ultrashort wavelength (7 femtoseconds) red laser pulse into a stream of neon atoms, where the stripped electrons were carried by the pulse and almost immediately re-eject into the neon nucleus.
While capturing the attosecond pulse, the physicists also demonstrated its utility. They aimed attosecond and longer-wavelength red pulses at a type of krypton atom simultaneously: first, the electrons were knocked off; then, the red light pulse hit the electrons; finally, the energy was tested. Judging from the difference in the timing of these two pulses, the scientists obtained a very precise measurement of how long it took the electron to decay (how many attoseconds). Never before have scientists used such a short time scale to study the energy of electrons.
The crystal lattice vibrates and molecules rotate on a scale of picoseconds. The creation and breaking of chemical bonds and molecular vibration happen in femtoseconds. Observing the motion of electrons happens on the attosecond scale.
The number of electrons in an atom and their configuration define an element. Because attosecond pulses are faster than the motion of electrons in atoms and molecules, attosecond provides a new tool for controlling and measuring quantum states of matter. These pulses have been used to explore the detailed physics of atoms and molecules and have potential applications in fields ranging from electronics to medicine.
Using a method called attosecond streaking, people can see the electrical components of EM waves. Scientists start with a gas of neon atoms and ionize them with a single ultrashort burst of UV radiation measured in attoseconds. The electric field of the infrared can then strongly influence the motion of the electrons. The electrons will be forced up and down as the field oscillates. Depending on when the electron is released, this process will emit different final energies. The final measurement of the electron's energy, as a function of the relative delay between the two pulses, clearly shows the traces of the electric field of the attosecond pulse.