Raskolnikov

Good point. Thank you. So how can the energy of a photon be determined more precisely?

Why not?

But since it's a LASER, all the photons must have the same energy, because they are all in the same exact quantum state. So it doesn't matter if the pulse is made of more than one photon, with the photoelectric effect we should still be able to calculate the energy of such photons since we know how many photons are produce and that they all have the same exact energy.

The shortest laser pulse ever produced is roughly between 3~10 fentoseconds. Due to the time-energy uncertainty principle, since we know so precisely the time period in which this phenemenon has occured, we need to have a big uncertainty in the energy of this photons. My question is: can't we produce such a short laser pulse and use the photoelectric effect to determine it's energy? If not, why not? If so, doesn't that violate the uncertainty principle?