Effects of laser polarization on photoelectron angular distribution through laser-induced continuum structure

Abstract

We theoretically investigate the effects of laser polarization on photoelectron angular distribution through laser-induced continuum structure. We focus on a polarization geometry where the probe and dressing lasers are both linearly polarized, and change the relative polarization angle between them. We find that the total ionization yield and the branching ratio into different ionization channels change as a function of the relative polarization angle, and accordingly the photoelectron angular distribution is altered. We present specific results for the 4p 1/2 -6p 1/2 and 4p 3/2 -6p 3/2 systems of the K atom, and show that the change of the polarization angle leads to the significant modification of photoelectron angular distribution.

Optical activity in the region of interfering laser-induced continuum structures

“…The structure of (+) is much more complicated as follows from (17), (18) and (20). The inverse matrix in (17) gives a denominator which is the third order polynomial of the probe field frequency .…”

“…The LICSs were first observed in the rotation of polarization of a probe field in the visible region (optical activity) 4 , in the cross section of the third-harmonic generation 5,6 , and later in the total and partial photoionization cross sections of a number of atoms [7][8][9][10][11][12][13][14] . Besides the photoionization cross section, modifications of angular distribution and spin polarization of photoelectrons in the region of LICS were studied theoretically [15][16][17] , including the direct numerical solution of the time dependent Schrödinger equation for femtosecond laser pulses 18 . The theoretical developments were mainly based on the assumption of featureless flat continuum 19,20 and reviewed, for example, in Ref.…”

Controlling the angular distribution of atomic photoelectrons in the region of laser-induced continuum structure in the femtosecond time domain

“…To date only very little is known about vector correlations in the region of LICS: the vast majority of previous publications deal with integral and hence angle-independent characteristics. There are a few theoretical papers on the angular distribution [23][24][25] and the spin polarization [26][27][28] of photoelectrons in the region of LICS, but more effort is needed to achieve a better understanding of the basic features. In particular, we are not aware of such studies in the femtosecond time domain.…”

“…The influence of LICS on the PAD raises a question about the possibility of controlling the PAD by manipulating the LICS. Indeed, Nakajima and Buica [24,25] predicted recently that the PAD formed by the probe radiation can be controlled by generating LICS: a dressing laser, coupling the (6p) 2 P discrete state of potassium to the continuum, can modify the branching ratio of ionization into the s-and d-continua. This causes changes in the PAD formed by ionization from the (4p) 2 P excited potassium state.…”

“…This causes changes in the PAD formed by ionization from the (4p) 2 P excited potassium state. The predictions of [24,25] were made for sufficiently long, nanosecond, laser pulses, and the PADs were supposed to be controlled by the two-photon frequency detuning and the polarization of the dressing laser.…”