Abstract

We report the results of an experiment showing how an opaque atomic transition in neutral Sr may be rendered transparent to radiation at its resonance frequency. This is accomplished by applying an electromagnetic coupling field (Fig. 1) between the upper state 4d5d¹D₂ of the transition and another state 4d5p ¹D₂ of the atom. When the Rabi frequency of the coupling field exceeds the inhomogeneous width of the 5s5p¹P₁−4d5d¹D₂ transition, the medium becomes transparent on line center. In this work, we have changed the transmittance of neutral strontium from exp(−20) without a coupling laser to exp(−1) in the presence of a coupling laser, over a spectral range of 6 GHz (Fig. 2). The coupling laser that we have used is a single mode Littman dye laser with an intensity of 10 MW/ cm² .

© 1991 Optical Society of America