Time-delayed Laser Pulses Research Articles

Isolated optical Ramsey fringes in the 32S–42D two-photon transitions of sodium

By inducing a 90° phase shift between pairs of coherent time-delayed laser pulses, and taking the difference between the fluorescence resulting from pairs of coherent pulses with and without the phase shift, we have eliminated the diffraction background and isolated the Ramsey’s interference fringes in the profile of Doppler-free two-photon resonances. This technique also offers enormous improvement for other situations in which interference fringe contrast is poor.