  A narrow elliptic ring containing an electron threaded by a magnetic field B
is studied. When the ring is highly flattened, the increase of B would lead to
a big energy gap between the ground and excited states, and therefore lead to a
strong emission of dipole photons. The photon frequency can be tuned in a wide
range by changing B and/or the shape of the ellipse. The particle density is
found to oscillate from a pattern of distribution to another pattern back and
forth against $B$. This is a new kind of Aharonov-Bohm oscillation originating
from symmetry breaking and is different from the usual oscillation of
persistent current.
