Dark line resonance in rubidium(87) due to coherent interaction with mode-locked lasers.

摘要

Spectroscopy of a A structure in 87Rb is performed with a mode locked laser. A dark line, resulting from population trapping between the hyperfine levels; is observed when the repetition rate is 1/57th of the hyperfine splitting. Simulation of coherent interaction of Rb atoms with laser pulses shows dark-lines corresponding to different submultiple of the hyperfine splitting. It is demonstrated experimentally and theoretically that the resonance width is insensitive to fluctuations in optical frequency. The intracavity implication of this insensitivity to optical frequency is to exploit the dark line resonance for stabilization of the repetition rate of a frequency comb. The error signal and the correction in this technique are purely optical. The correction is made through a change in pulse group delay opposing a change in cavity length.