The discovery of superconductivity at 203 K in ${\mathrm{SH}}_{3}$ is an important step toward higher values of critical temperature ${T}_{c}$. Predictions based on state-of-the-art density functional theory for the electronic structure, including one preceding experimental confirmation, showed the mechanism to be the electron-phonon interaction. This was confirmed in optical spectroscopy measurements. In the range of photon energies between $\ensuremath{\sim}450$ and 600 meV in ${\mathrm{SH}}_{3}$, the reflectance in the superconducting state is below that in its normal state. This difference decreases as temperature approaches ${T}_{c}$. Decreasing absorption with increasing temperature is opposite to what is expected in ordinary metals. Such an anomalous behavior can be traced back to the energy dependence of the superconducting density of states, which is highly peaked at the energy gap value $\mathrm{\ensuremath{\Delta}}$ but decays back to the constant normal state value as energy is increased, on a scale of a few $\mathrm{\ensuremath{\Delta}}$, or by increasing temperature towards $T={T}_{c}$. The process of phonon-assisted optical absorption is encoded with a knowledge of the temperature dependence of $\mathrm{\ensuremath{\Delta}}$, which is also the order parameter characteristic of the superconducting state. Should the energy of the phonon involved be very large, of order 200 meV or more, this process offers the possibility of observing the closing of the superconducting order parameter with temperature at correspondingly very large energies. The very recent experimental observation of a ${T}_{c}\ensuremath{\simeq}250$ K in ${\mathrm{LaH}}_{10}$ has further heightened interest in the hydrides. Here, we compare the relevant phonon structure seen in optics with related features in the real and imaginary part of the frequency dependent gap, the quasiparticle density of states, the reflectance, the absorption, and the optical scattering rate. The phonon structures all carry information on the ${T}_{c}$ value and the temperature dependence of the order parameter, and can be used to confirm that the mechanism involved in superconductivity is the electron-phonon interaction.