  A moving boundary separating two otherwise homogeneous regions of a
dielectric is known to emit radiation from the quantum vacuum. An analytical
framework based on the Hopfield model, describing a moving refractive index
step in 1+1 dimensions for realistic dispersive media has been developed in
[1]. We expand the use of this model to calculate explicitly spectra of all
modes of positive and negative norm. Furthermore, for lower step heights we
obtain a novel set of mode configurations. This leads to a realistic emission
spectrum featuring black hole- and white hole emission for different
frequencies. We also present spectra as measured in the laboratory frame that
include all modes, in particular a dominant negative norm mode, which is the
partner mode in any Hawking-type emission. We find that the emission spectrum
is highly structured into intervals of emission with black hole-, white hole-,
and no horizons. Finally we estimate the number of photons emitted as a
function of the step height and find a power law of 2.5 for low step heights.
