no offense, as you are a much more experienced player than i. however, where did you induce the bluff?

he could have slowed the flush w/ KcXc.
he could feel his Q is good when you check the A and flush, and could be thinking it is YOU that is bluffing, and he could be good.

couldnt you be just as easily up against A5s or AJ?

i guess i dont see how you induced a bluff, as if you pwned this guy, when it looks like a standard line w/o a cbet to me.