In physics, ultrafast describes events that occur on femtosecond timescales. It was once impossible to observe anything that happened on this timescale due to the speed limitations of electronics and other experimental apparatus, but with advances in pulsed dye lasers and later the creation of the pulsed Ti:sapphire laser, which when mode-locked can create pulses as short as ten femtoseconds, this regime has become accessible.

Applications

The ability to study something that happens on very short timescales is useful in many fields of science. Ultrafast lasers are currently being used in many applications including: to study the femtosecond dynamics of electrons in solids, to create small, tabletop-sized fusion experiments, to manipulate and monitor chemical reactions, to modify and image magnetic surfaces, and to create and study plasmas. They have also been used extensively in microscopy.

The 1999 Nobel Prize in Chemistry was awarded to Ahmed H. Zewail for using ultrashort pulses to observe chemical reactions on the timescales they occur on, opening up the field of femtochemistry.

External links

• Virtual Jounal of Ultrafast Science