The Optimization of Cold Rubidium Atom Two-Photon Transition Excitation with an Erbium-Fiber Optical Frequency Comb

We demonstrated the observation of cold rubidium atom two-photon transition excitation by a fiber optical frequency comb. In addition to this, we optimized the repetition rate of optical frequency comb to enhance two-photon intensity by controlling cavity length and pump source of optical comb. This technique can fine tune repetition rate to corresponding stepwise two-photon transition resonance frequency and improve the transition intensity by three times. This method is useful in Doppler laser cooling and detection of macromolecules.