In that case you would need to open all Word documents with Word itself, using the COM object Word.Application
. Then you can look at the document's metadata using the ContentTypeProperties collection on the Document object. The author name, if present, would be in that collection.
This will take a while, however, so maybe you could just take a look at the file system ACLs to determine who created the file? But that tells you only the user who created the file, not the person who created the document.
Another option would probably be to use Windows Search from within Powershell. Apparently you can use it with an OLE DB provider. And I think Windows Search is able to query author information from Word documents.