Abstract

High-order harmonics as a potential source of coherent XUV have resulted in extensive studies of this effect. One of the limitations to the efficiency of the generation process is the phase shift occurring at the focus of a gaussian beam (Goyd factor) [1]. This can be minimized by using long focal length and setting the atomic jet either before or after the focus. Self-guided beams are an attractive alternative to focused beams since they can, in principle, be made intense enough while their phase front remains flat in the high intensity region. This is because the curvatures of the wavefront due to diffraction and the Kerr effect compensate each other.

© 1997 Optical Society of America