Kasevich hopes to improve the method and cool atomic gases to quadrillionths
of a kelvin.
An atom's mass/energy occupies "only a few quadrillionths
of its volume" (Hewitt, 2002, p.
The pulses of some lasers are so brief--a few quadrillionths
of a second--that they can visually freeze the lightning-fast movements of molecules in a chemical reaction.
The object selected was a single bacterium, Spiroplasma Milliferum, made at 150-nanometer resolution and computer-refined to 75 nanometers, but requiring an exposure to the beam of just 15 femtoseconds (quadrillionths
of a second).
The new device, which consistently generates pulses of light lasting just femtoseconds (quadrillionths
of a second) in the ultraviolet region of the electromagnetic spectrum, was described in the May 20, 2005 issue of Physical Review Letters.
The laser pulse lasted only 150 femtoseconds, or 150 quadrillionths
of a second.
Preliminary experiments from three countries indicate that when ultrashort light pulses (less than 40 quadrillionths
of a second) are used, electrons might be accelerated by a novel mechanism in which laser light directly accelerates the electrons rather than indirectly through plasma oscillations.
A breakthrough in laser pulsing in 1987 led researchers to create femtosecond (quadrillionths
of a second) laser bursts to track step-by-step specific details of chemical reactions-- bonding and decoupling, for example--as they are occurring.
It was made possible with SLAC's instrument for ultrafast electron diffraction (UED), which uses energetic electrons to take snapshots of atoms and molecules on timescales as fast as 100 quadrillionths
of a second.
But at about 50 quadrillionths
of a second in duration, such short pulses can't deliver enough energy to remotely power an aircraft or burn a hole through an incoming intercontinental ballistic missile.
The LCLS experiment also showed researchers how the electronic structure of the sample rearranged into non-conducting "islands" surrounded by electrically conducting regions, which began to form just hundreds of quadrillionths
of a second after a laser pulse struck the sample.