How does laser cooling work?

Well, its true photons of light carries momentum. Its very noticeable with a Q-Switched Nd:Yag laser, when you put a piece of carbon paper right in front of the laser output, the beam from the Nd:Yag laser actually pushes the carbon paper as it hits, followed by a "snapping sound" :-)
Perhaps, the "pushing" can be used for laser cooling? 

Great video by the way.