  We calculate the Raman response for the Kitaev spin model on the
$\mathcal{H}$-$0$, $\mathcal{H}$-$1$, and $\mathcal{H}$-$\infty$ harmonic
honeycomb lattices. We identify several quantitative features in the Raman
spectrum that are characteristic of the spin liquid phase. Unlike the dynamical
structure factor, which probes both the Majorana spinons and flux excitations
that emerge from spin fractionalization, the Raman spectrum in the Kitaev
models directly probes a density of states of pairs of fractional, dispersing
Majorana spinons. As a consequence, the Raman spectrum in all these models is
gapless for sufficiently isotropic couplings, with a low-energy power law that
results from the Fermi lines (or points) of the dispersing Majorana spinons. We
show that the polarization dependence of the Raman spectrum contains crucial
information about the symmetry of the ground state. We also discuss to what
extent the features of the Raman response that we find reflect generic
properties of the spin liquid phase, and comment on their possible relevance to
$\alpha-$, $\beta-$ and $\gamma-$Li$_2$IrO$_3$ compounds.
