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Chirality causes symmetry breaks in a large variety of natural phenomena ranging from particlephysics to biochemistry. We investigate one of the simplest conceivable chiral systems, a laser-excited, oriented, effective one-electron Li target. Prepared in a polarized p state with |m|= 1 in an optical trap, the atoms are exposed to co- and counterrotating circularly polarized femtosecond laser pulses. For a field frequency near the excitation energy of the oriented initial state, a strongcircular dichroism is observed and the photoelectron energies are significantly affected by the helicity-dependent Autler-Townes splitting. Besides its fundamental relevance, this system is suited to create spin-polarized electron pulses with a reversible switch on a femtosecond timescale at an energy resolution of a few meV.
Available at: http://works.bepress.com/daniel-fischer/85/
The experimental material presented here is based upon work supported by the National Science Foundation under Grant No. PHY-1554776.