  We report an experimental investigation of electromagnetically induced
transparency in a multi-level cascade system of cold atoms. The absorption
spectral profiles of the probe light in the multi-level cascade system were
observed in cold Rb-85 atoms confined in a magneto-optical trap, and the
dependence of the spectral profile on the intensity of the coupling laser was
investigated. The experimental measurements agree with the theoretical
calculations based on the density matrix equations of the rubidium cascade
system.
