Abstract

Recent measurements of the kinetic energies of photoelectrons produced in multiphoton ionization of the rare gases for ultra-short (≤ 250 femtosec), high intensity (≈10¹⁴W/cm²) light near 616 nm reveals a complex spectra, rich in structure with some features so narrow in energy that they are limited by the spectrometer resolution. In this paper I show that this thoroughly unanticipated result is a signature of a general phenomena, one that is present (but often hidden) in all multiphoton experiments regardless of the pulse length employed in the particular experiment. Further, I argue this phenomena is directly related to the ponderomotive potential associated with the "wiggle" motion that an electron executes under the influence of an intense optical field.

© 1988 Optical Society of America