Experimental results from the generation of Raman sidebands using optical vortices are presented. By generating two sets of sidebands originating from different locations in a Raman active crystal, one set containing optical orbital angular momentum
and the other serving as a reference, a Youngs double slit experiment was simultaneously realized for each sideband. The interference between the two sets of sidebands was used to determine the helicity and topological charge in each order. Topological charges in all orders were found to be discrete and follow selection rules predicted by a cascaded Raman process.
We present experimental results for the ionization of aniline and benzene molecules subjected to intense ultrashort laser pulses. Measured parent molecular ions yields were obtained using a recently developed technique capable of three-dimensional im
aging of ion distributions within the focus of a laser beam. By selecting ions originating from the central region of the focus, where the spatial intensity distribution is nearly uniform, volumetric-free intensity-dependent ionization yields were obtained. The measured data revealed a previously unseen resonant-like multiphoton ionization process. Comparison of benzene, aniline and Xe ion yields demonstrate that the observed intensity dependent structures are not due to geometric artifacts in the focus. Finally we attribute the ionization of aniline to a stepwise process going through the pi-sigma^star state which sits 3 photons above the ground state and 2 photons below the continuum.
