Deflect most often is used in a sense of deflecting something away from something else. e.g. to deflect a bullet. That would mean away from its target, not into a target.

In English there isn't a general word for altering a trajectory into an object. In this case however, reflect is precisely suited to what mirrors do to light and doesn't have the confusing inverse connotation of away. You reflect away from something or onto something equally well in English.