Intense Light Field Control

Processes emerging from the interaction of intense, ultrashort-pulsed radiation with matter play an increasingly important role in physical, chemical and biological sciences as well as in technology. Ultrashort light pulses are capable of changing the physical properties, the chemical composition and the biological function of matter. Controlling the temporal variation of the intensity and frequency of ultrashort pulses recently allowed breaking selected chemical bonds in molecules and thereby steering - for the first time - chemical reaction dynamics. In a similar way, ultrashort-pulsed irradiation may modify the structure and hence influence the biological function of organic macromolecules, e.g. proteins. Ultrafast light flashes can also launch and control electric current in basic (semiconductor) components of electronic circuits and pave the way towards faster, more powerful computers and telecommunications systems. The ultimate scale of time relevant for the motion of atoms in molecules (which change the structure determining the chemical and biological properties) and for the creation or annihilation of charged carriers and their transport dynamics in semiconductors (which determine the speed of electronic devices), is the femtosecond time scale. Laser pulses with a durations down to less than 10 fs are now available, permitting triggering these processes and subsequently following their evolution in time. The impact of these advances on chemical and biological sciences was acknowledged by the 1999 Nobel Prize in chemistry. Is there a need for control and measurement on an even shorter time scale of around 1 fs or less? Definitely! Strongly excited atoms return into their ground state by electron relaxation processes within a period of typically less than a femtosecond and upon doing so, they release energy by emitting X-rays. These extraordinarily fast, inner-atomic processes are of crucial importance for the development of efficient, compact, laser-like sources of X- rays, which would impact a wide range of fields in science and technology. Control of and insight into these processes require the evolution of the electromagnetic field in laser light to be controlled within the oscillation period, which amounts to 1-3 fs, depending on the color of radiation. Control and measurement of the electromagnetic field in intense light waves will allow looking into atomic dynamics and manipulating it on a sub- femtosecond (< 1fs) time scale. The development of this unprecedented technical capability, which is the central objective of this project, is likely to dramatically push the frontiers of several fields in science and technology.

This project resulted in the development of a high-power source of laser light producing laser pulses that comprise merely a few wave cycles with a perfectly controlled shape of the electromagnetic fields. This achievement was published in Nature in 2003 and identified as one of the most frequently cited recent paper in Physical Sciences by ESI (www.esi-topics.com/nhp/2004/may-04-FerencKrausz.html). Controlled light waves allow - for the first time - steering electrons in the interior of atoms and molecules on the natural - attosecond - scale of their motion and open entirely new prospects in the exploration and control of the microcosm. Implications of the new attosecond technology based on these light waves include the development of faster electronics and ultimate control of chemical reactions and changes in the configuration (and hence function) of biomolecules.