Abstract
The ac Stark shift (or light shift) of the transition in Cs, as observed through coherent population trapping under pulsed excitation, is measured using a Cs gas cell and the -line vertical-cavity surface-emitting laser. This light shift can be calculated using density-matrix analysis. We derive an expression for this shift as a function of light intensity, showing that it varies linearly with respect to light intensity only with intensities higher than 1.0 mW/cm. For pulsed excitation of high laser intensity, the variation in light shift is 20 times lower than that when using a continuous wave. The differences between the results of theory and experiment are discussed, taking into account the difference in conditions assumed; the results from theoretical analysis, taking the attenuation of the first-order sideband into account, approximately agree with the experimental results. The light shift is reduced by shortening the observation times.
1 More- Received 16 December 2013
- Revised 10 June 2014
DOI:https://doi.org/10.1103/PhysRevA.90.013826
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