Ultracold Rydberg Atoms and Terahertz Spectroscopy

The objective of our research is to study the interaction of highly excited, or Rydberg atoms, with unipolar terahertz electromagnetic pulses (half cycle pulses). These systems provide a fascinating regime in which to explore atomic states which exhibit both classical and quantum properties. In particular, these pulses provide an impulsive kick to the excited electron and thus interact in a much different manner than traditional bipolar continuous wave laser radiation.
The first series of experiments in my group will explore the interaction of a train of these pulses with Rydberg atoms. Hu and Collins have suggested that application of a certain number of these pulses should drive the Rydberg atoms to lower n quantum states. In principle this broadband technique should allow the efficient de-excitation of antihydrogen atoms from the currently produced mix of excited states to the ground state which is a necessary for prerequisite for a CPT comparison with hydrogen.
Further research will include the study of the magnetic properties of the half cycle pulse and their effect on atomic systems. In addition, carefully shaped half cycle pulse may be able to produce interesting atomic and molecular wavefunctions such as the trilobite states initially proposed by Greene et al.

References

• S. X. Hu and L. A. Collins, Phys. Rev. A, 89, 041402 (2004).



• C. H. Greene, A. S. Dickinson, and H. R. Sadeghpour, “Creation of Polar and Nonpolar Ultra-Long-Range Rydberg Molecules”, Physical Review Letters, 85 , 2458 (2000).