Abstract

Electrons injected into a high intensity laser focus by tunneling ionization quickly escape due to the strong ponderomotive force. This limits the probability of observing harmonic radiation from free electrons oscillating in the field¹ and other nonlinear effects. Two dimension(radial) optical confining schemes have been proposed to increase the life-time of the electron in the intense field.^2,3 These do not confine the electron in the direction of the laser propagation which limits their effectiveness. In intense fields the electrons have significant momentum in this direction.⁴ To our knowledge, neither of these schemes have been demonstrated.

© 1997 Optical Society of America