Personally i have another pop at the pot, as you say you have little idea what he has.
You can't afford to check raise so a bet of around 1200 will get an answer
But the pot is 2400 so won't that bet look weak and encourage him to reraise you on a bluff (maybe that's just what i would do in his position).
well, if thats the case, its much better then simply pushing, as nemesis advocates, because it widens the range of hands your opponent is playing against you. In fact, thats probably the best reason for betting such an amount.
I don't think checking is bad at all though, the only free card you fear is a diamond, which doesn't come very often anyways, but it enables your opponent to think he is value betting 2pr which subsequently gets him stuck to the pot (which might fold in the face of that board and an overbt all in), and it enables him to try and steal the pot, giving you much more dead money when u bomb the pot afterwards... it might even get him off a 10 if he is a scared ass mo-fo (but thats wishful)