Abstract

An interesting phenomenon associated with high-order harmonic generation is the development of an intrinsic phase variation at the atomic level between the phase of the laser field and the phase of the emitted harmonic light. We created experimental conditions where the harmonics could be thought of as emerging from a single plane rather than a 3-dimensional volume.^1,2 The appearance of broad wings (carrying ~75% of the energy) in the harmonic farfield angular profiles under such conditions indicates the presence of strong intensity-dependent intrinsic phases. The diffraction of the individual harmonics which causes the wings occurs because intrinsic phases translate into radial phase variations in the laser focus according to the intensity distribution.

© 1994 Optical Society of America