I haven't done this quest myself (I have only just started the prior quest 'Good Intentions' in my playthrough, so I am not even at the same stage as you). I searched for information regarding this quest, and I found something that may be useful. Here is the web site.
http://www.uesp.net/wiki/Skyrim:Revealing_the_Unseen
I have cut-and-pasted below, the part that is relevant to you;
----------------------------------------------------------------------------------------
"After turning in Revealing the Unseen, there's a bug where you do not get the next quest. No known fix. The bug comes when Mirabelle's second dialogue bit in stage 99 is instead the standard conversation options. Nobody acknowledges the events of this quest and even Ancano walks around and talks to you as usual. Some workarounds have been tried but it is not possible to activate the next quest (MG05 - http://www.uesp.net/wiki/Skyrim:Containment) because it is numbered wrongly.
- Update 26/11 21:04 It fixes itself after playing some other quests, not empirically measured, but probably related to in-college quests. Just save before talking to the arch Mage, keep playing other quests and come every now and then to check whether it is fixed. Try also deleting any dragon skeletons that you may have in the college using console command "disable" after clicking them."
----------------------------------------------------------------------------------------
From reading this, it sounds like either;
A. the quest is broken and can never be started. Or,
B. the triggering of the 'revealing the unseen' quest is related to the completion of other quests in the college.
Try the following steps;
1. Go back to a savegame before you have spoken to the arch mage, i.e. after you completed 'Good intentions' but before talking to her to get the 'revealing the unseen' quest.
2. If she doesn't give you 'Revealing the unseen' quest, reload the savegame and talk to other NPC's in the college and complete that quest they give you. When completed, save the game and then talk to the arch mage again. If you still don't get the quest, reload your savegame and continue talking to other NPC's in the college.
The idea is, that one of the quests from one of the other NPC's in the college is preventing the arch mage giving you the 'Revealing the unseen' quest. Which particular quest you will need to complete in order to trigger the 'revealing the unseen' quest is likely to depend upon the state of your game, and what quests have already been done. Complete any quests you find from other NPC's, and hopefully you will eventually trigger the 'Revealing the unseen' quest.