  The law of reflection states that smooth surfaces reflect waves specularly,
thereby acting as a mirror. This law is insensitive to disorder as long as its
length scale is smaller than the wavelength. Monolayer graphene exhibits a
linear dispersion at low energies and consequently a diverging Fermi
wavelength. We present proof that for a disordered graphene boundary, resonant
scattering off disordered edge modes results in diffusive electron reflection
even when the electron wavelength is much longer than the disorder correlation
length. Using numerical quantum transport simulations, we demonstrate that this
phenomenon can be observed as a nonlocal conductance dip in a magnetic focusing
experiment.
