MongoDB Full Text on an Array within an Array of Elements
Text search does not currently support indexed fields of nested arrays (at least not explicitly specified ones). An index on "foo.name" works fine as it is only one array deep, but the text search will not recurse through the subarray at "foo.data.text". Note that this behavior may change in the 2.6 release.
But fear not, in the meantime nested arrays can be text-indexed, just not with individually specified fields. You may use the wildcard specifier $** to recursively index ALL string fields in your collection, i.e.
db.collection.ensureIndex({"$**": "text" }as documented at http://docs.mongodb.org/manual/tutorial/create-text-index-on-multiple-fields/ . Be careful though as this will index EVERY string field and could have negative storage and performance consequences. The simple document structure you describe though should work fine. Hope that helps.