  Weyl points, serving as monopoles in the momentum space and laying the
foundation of topological gapless phases, have recently been experimentally
demonstrated in various physical systems. However, none of the observed Weyl
degeneracies are ideal: they either offset in energy or coexist with trivial
dispersions at other momenta. The lack of an ideal Weyl system sets a serious
limit to the further development of Weyl physics and potential applications.
Here, by constructing a photonic metamaterial, we experimentally observe an
ideal Weyl system, whose nodal frequencies are pinned by symmetries to exactly
the same value. Benefitting from the ideal Weyl nodes, we are able to map out
the complete evolution of the helicoid surface states spinning around the
projections of each Weyl nodes. Our discovery provides an ideal photonic
platform for Weyl systems and novel topological devices.
