Measurement of Dicke Narrowing in Electromagnetically Induced Transparency

D ickenarrowing isaphenom enathatdram atically reducestheD opplerwidth ofspectrallines,due tofrequentvelocity-changingcollisions.A sim ilarphenom enaoccursforelectrom agnetically induced transparency (EIT) resonances,and facilitates ultra-narrow spectralfeatures in room -tem perature vapor. W e directly m easure the D icke-like narrowing by studying EIT line-shapes as a function ofthe angle between the pum p and the probe beam s. The m easurem ents are in good agreem ent with an analytic theory with no (cid:12)tparam eters.Theresultsshow thatD ickenarrowing can increase substantially the tolerance ofhot-vapor EIT to angular deviations. W e dem onstrate the im por-tance ofthise(cid:11)ectforapplicationssuch asim aging and spatialsolitonsusing a single-shotim aging experim ent,and discussthe im plicationson the feasibility ofstoring im ages in atom ic vapor. ofD