Intense Laser-Atom Physics in Scaled Interactions

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This project undertakes a comprehensive study of the single atom response under novel interaction conditions that will not only provide basic tests of scaling laws and theory but also initiate some unique experimental investigations in strong field physics. The overall objective of the project is to broaden the scope of experimental investigations by utilizing the wavelength scaling of the strong field interaction in the regime where the photon energy is much smaller than the atomic binding energy. Various aspects of the strong-field interaction have an implicit wavelength-dependence that is a crucial scaling parameter and has not been explored or exploited in a systematic fashion. Addressing these scaling laws with novel ionization experiments using few-cycle mid-infrared (2 micron and 4 micron wavelength) pulses is crucial since it tests the very foundations of all our understanding of the intense laser-atom interaction. Using these principles a number of key studies will be enabled and include significantly increasing the number of atomic systems capable of experiencing intense laser fields, allowing systematic studies of one- and two-electron systems, and examining strong field interactions for prepared states and initiate a global investigation of scaling laws.The interaction of an isolated atom with an intense electromagnetic field is the basis for one of the forefront problems in atomic, molecular and optical physics. The ability to couple large amounts of energy into an atom by the absorption of many photons posed many intriguing questions and has led to many new discoveries such as above-threshold ionization, high-harmonic generation, multiple ionization and adiabatic stabilization. At the core of the problem is the non-perturbative response of the atom to a laser pulse that imposes an external field comparable to the forces binding the electrons to the nucleus. The continuing interest in this fundamental atomic physics problem is derived from its broad implications in other areas of physics and technology. The single atom response is the initial condition of more complex phenomena found in plasmas, inertial confined fusion concepts, advance particle acceleration and astrophysics. The intense laser-atom interaction itself is opening new opportunities in short wavelength science, quantum control and advancing an emerging discipline in hyperfast electron physics, attophysics. Recently, the optical techniques used for producing the ultra-fast laser pulses for these studies have reached a level of sophistication where the electromagnetic field can be completely determined, i.e. absolute phase and amplitude. Furthermore, the interdisciplinary nature of this research coupled with state-of-the-art ultra-fast optical technology provide an excellent training ground for both undergraduate and graduate students.