  We report that the polarizations of sidebands emitted from bulk gallium
arsenide (GaAs) driven by a strong terahertz (THz) laser while probed with a
weak near-infrared laser can be viewed as interferograms from a Michelson-like
interferometer for Bloch waves. A simple analytical model is introduced to
calculate the difference in quantum mechanical phases accumulated by Bloch
waves associated with electron-heavy hole and electron-light hole pairs in
their respective interferometer arms. The measured and calculated spectra are
in good quantitative agreement, including scaling with THz field strength. Our
results indicate a simple way to extract material parameters in future
experiments
