If I read that correctly (not material for a rapid scan), because velocity and mass of the photon aren't going to change, the energy shows up as wavelength.
PatrickHenry says: "...
because velocity and mass of the photon aren't going to change, the energy shows up as wavelength."
Close, but keeping in mind that the photon has no real mass, let's rewrite your statement like this:
"Because velocity of the photon and Planck's constant aren't going to change, the momentum (change) shows up as wavelength (change)."
--Boot Hill