Abstract
We report a c-axis-polarized electronic Raman scattering study of
Bi_2Sr_2CaCu_2O_{8+\delta} single crystals. In the normal state, a resonant
electronic continuum extends to 1.5 eV and gains significant intensity as the
incoming photon energy increases. In the superconducting state, a coherence
2\Delta peak appears around 50 meV, with a suppression of the scattering
intensity at frequencies below the peak position. The peak energy, which is
higher than that seen with in-plane polarizations, signifies distinctly
different dynamics of quasiparticle excitations created with out-of-plane
polarization.