  We experimentally investigate electromagnetically-induced transparency (EIT)
created on an inhomogeneously broadened 5S_1/2-5P_1/2 transition in rubidium
vapor using a control field of a complex temporal shape. A comb-shaped
transparency spectrum enhances the delay-bandwidth product and the light
storage capacity for a matched probe pulse by a factor of about 50 compared to
a single EIT line [D. D. Yavuz, Phys. Rev. A 75, 031801 (2007)]. If the
temporal mode of the control field is slowly changed while the probe is
propagating through the EIT medium, the probe will adiabatically follow,
providing a means to perform frequency conversion and optical routing.
