Optical frequency combs have in the recent past revolutionized the field of high-resolution spectroscopy by beingapplied both as frequency references and light sources for direct comb spectroscopy. With respect to the latterapplication, we have demonstrated the use of an optical frequency comb to coherently drive stimulated Ramantransitions between terahertz-spaced atomic energy levels. Specifically, we have measured the 3d ~2D_(3/2) - 3d ~2D_(5/2) finestructure splitting of a single trapped 40Ca+ ion to be 1,819,599,021,534±8Hz, which is five times more accurate thanprevious measurements, and currently only limited by the stability of our atomic clock reference. Furthermore, Rabioscillations with a contrast of 99.3(6)% and millisecond coherence time have been realized experimentally, indicatinggreat potentials for future qubit applications. Importantly, the technique should generally be applicable to drive Ramantransitions spanning the level spacings ranging from sub-kHz to tens of THz range, including hyperfine transitions inhighly charged ions and spin-resolved rovibrational transitions in molecular ions. High-resolution spectroscopy of suchsystems may find applications in the search for new physics beyond the Standard Model.
展开▼
