FARIA2	Coulomb focusing and interference effects in above-threshold ionization with elliptically polarized fields
Type	Theoretical
#students	1
Orientation	Why is the scientific problem of interest at all? An important application of the interaction between strong laser fields (intensities of 10^13W/cm^2or higher) and matter is the possibility of imaging and steering electron dynamics with sub femtosecond precision. This may have applications in several areas of knowledge, such as physics, chemistry and biology. The fact that strong-field phenomena may be described as laser-induced collision processes of an electron and its parent ion allows one to describe these dynamics analytically. For an accurate imaging, however, it is necessary to assess the role of the residual binding potentials, which are not present in standard strong-field models. In particular the influence of this potential on quantum interference effects is not fully understood.
How	How is the research going to shed light on the given problem?. Above-threshold ionization is a strong-field phenomenon in which a system absorbs more photons than the necessary amount for it to ionize. ATI spectra may extend to very high photoelectron energy, and exhibit a series of interference patterns. In analytic models it is common to approximate the continuum by field-dressed plane waves, i.e., to neglect the influence of the residual binding potentials. It has been found, however, that the interplay between the Coulomb potential and the strong laser field plays an important role in describing several features, such as a fan-shaped structure observed in differential photoelectron spectra [1].
What	What is the specific thing that the student will do, and how does it fit inside the overall project? In this project, the student will extend the work performed in [2] in which quantum interference in direct ATI has been studied, and make a detailed analysis of the influence of the Coulomb potential in the interference patterns, for linearly and elliptically polarized fields. These results will be compared to experimental [1] and theoretical [3] findings by other groups. The student will employ an analytic, Coulomb-corrected approach and the steepest descent method.
Special Knowlegde	Mathematica and/or C++
Supervisor	Dr Carla Faria c.faria@ucl.ac.uk For more information please contact Dr Carla Faria (c.faria@ucl.ac.uk) or see the website http://www.homepages.ucl.ac.uk/~ucapcfi/ [1] A. Rudenko et al, J. Phys. B 37, L407 (2004); C. M. Maharjan et al, J. Phys. B. 39, 1955 (2006). [2] Xuanyang Lai and C. Figueira de Morisson Faria, Phys. Rev. A 88, 013406 (2013). [3] D. Arbo et al, Phys. Rev. Lett. 96, 143003 (2006); T. M. Yan et al, Phys. Rev. Lett. 105, 253002 (2010).