Polarization Control of Differential Cross Sections

Rather than attempting coherent control with two different frequencies, it appears that using two different polarizations of the same frequency would be much easier to implement experimentally. It turns out that this scenario is akin to the one- vs. two tf photon control in the sense that integral control is not possible. Although differential cross sections can be controlled [90], one cannot break the forward-backward) symmetry in this case..  

To see this, we consider the photodissociation of a single bound state EX) byif)i single cw source with arbitrary polarization vector 

We can regard the two components and fi2 as inducing two independ excitation routes. Choosing e, and 2 parallel and perpendicular to the quantize (z) axis, respectively, the differential cross section is composed of three terras) corresponds to photodissociation of E ) by the gj component, one by the- component, and one being the cross term between these two contributions. Ex) tion by the parallel component allows AM, = 0 transitions, while excitation by) 

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