  The helicity representation of the linear momentum density of a light wave is
well understood for monochromatic optical fields in both paraxial and
non-paraxial regimes of propagation. In this note we generalize such
representation to nonmonochromatic optical fields. We find that, differently
from the monochromatic case, the linear momentum density, aka the Poynting
vector divided by $c^2$, does not separate into the sum of right-handed and
left-handed terms, even when the so-called electric-magnetic democracy in
enforced by averaging the electric and magnetic contributions. However, for
quasimonochromatic light, such a separation is approximately restored after
time-averaging. This paper is dedicated to Sir Michael Berry on the occasion of
his $80$th birthday.
