  We compare efforts to extract self energies and fluctuation spectra of the
cuprates using optical and photoemission techniques. The fluctuations have
contributions from both the coherent and incoherent parts of the band, which
are spread over the full bare bandwidth of >2eV. Many experimental studies
concentrate on the coherent part of the band and hence miss higher energy
fluctuations. Our study establishes the universal presence of high energy
bosonic fluctuations across various spectroscopies as a key ingredient in the
high temperature superconducting cuprates.
