  For the high-order harmonic generation in solids, we find a distinct and
clean interference pattern in the high-energy end of the spectrum which can be
interpreted as a Michelson interferometer of the Bloch electron. Our results
are achieved by a numerical solution to the time-dependent Schr\"odinger
equation of the quasi-electron in solids and can be explained by an analytical
model based on the principle of the Michelson interferometry.
  The present study deepens our understanding of the HHG mechanism in
crystalline materials and may find potential applications in imaging of the
dispersion relation or topological structure of the energy bands in solids.
