How does laser cooling work?

wait, but.... how can light carry momentum if photons have no mass?
So,  according to my grade 10 physics mv=p  so if we have mass 0 equation will be 0*300000000=p and 0 times 300000000 will give 0, so 0 momentum. Am I correct? So sad I have summer vacation otherwise tomorrow morning I would have run to my physics teacher the moment I got feet in school. Could be something that has to do with the quantum properties of the photons? Diana, could you explain?