  Compact orbiting binaries like the black hole binary system observed in
GW150914 carry large amount of orbital angular momentum. The post-ringdown
compact object formed after merger of such a binary configuration has only spin
angular momentum, and this results in a large orbital angular momentum excess.
One significant possibility is that the gravitational waves generated by the
system carry away this excess orbital angular momentum. An estimate of this
excess is made. Arguing that plane gravitational waves cannot possibly carry
any orbital angular momentum, a case is made in this paper for gravitational
wave beams carrying orbital angular momentum, akin to optical beams.
Restricting to certain specific beam-configurations, we predict that such beams
may produce a new type of strain, in addition to the longitudinal strains
measured at aLIGO for GW150914 and GW170817. Current constraints on
post-ringdown spins, derived within the planewave approximation of
gravitational waves, therefore stand to improve. The minimal modification that
might be needed on a laser-interferometer detector (like aLIGO or VIRGO) to
detect such additional strains is also briefly discussed.
