  This study presents a method based on the total internal reflection and the
phase-shifting interferometry for measuring the Van Hove singularities in
strained graphene. A linearly polarized light passes through some quarter- and
half-wave plates, a hemi-cylindrical prism, and a Mach-Zehnder interferometer.
The Van Hove singularities manifest themselves as some sharp dips or peaks in
the spectrum of the final phase difference of the two interference signals. The
numerical analysis demonstrates that the number of Van Hove singularities is
independent of the modulus of the applied stress, but their position shifts as
the strength of the tension increases. Besides, the number and location of
singularities strongly depend on the stress direction relative to the zigzag
axis in the graphene lattice. Moreover, we show that the location of
singularities is independent of the tension direction relative to the
tangential component of the electric field of the incident radiation.
