  We present a beam splitter in a suspended, ballistic, multiterminal, bilayer
graphene device. By using local bottomgates, a p-n interface tilted with
respect to the current direction can be formed. We show that the p-n interface
acts as a semi-transparent mirror in the bipolar regime and that the
reflectance and transmittance of the p-n interface can be tuned by the gate
voltages. Moreover, by studying the conductance features appearing in magnetic
field, we demonstrate that the position of the p-n interface can be moved by
$1\,\mu$m. The herein presented beamsplitter device can form the basis of
electron-optic interferometers in graphene.
