  Nonlinear optical effects in vacuum have been investigated as a means to
verify quantum electrodynamics in a region of low photon energy. By considering
nonlinear electromagnetic waves in a three-dimensional cylindrical cavity, we
report that the orbital angular momentum of light strongly affects
self-modulations in a long timescale. The variation in optical phase is shown
to enhance the vacuum nonlinearity. Moreover, we demonstrate the time evolution
of the energy transfer between cavity modes and of the phase shift, paving new
possibility for verification experiments.
