  The slight deformations observed upon transmission of a light pulse through a
short length of a silica glass nano-filament offer the possibility of
determining the momentum of light inside the filament. Using precise numerical
calculations that take into account not only the electromagnetic momentum
inside and outside the filament, but also the Lorentz force exerted by a light
pulse in its entire path through the nano-waveguide, we conclude that the net
effect of a short pulse exiting the nano-filament should be a pull force on the
end face of the filament.
