How to search for all the content in the index using unindexed filed value like URLs using index of zend_search_lucene?

Question

I am using zend_search_Lucene for indexing files and its contents.

below is the code I am using:

    $index=$index = new Zend_Search_Lucene('/home/project/news4u/data/search_file/lucene.customer.index', new);
    $doc = new Zend_Search_Lucene_Document();
    $doc->addField(Zend_Search_Lucene_Field::unIndexed('URL', $file1_path));
    $doc->addField(Zend_Search_Lucene_Field::text('contents',$content));
    $index->addDocument($doc);              

Now I want to see all the URLs in indexed files: field name URL is of type 'unIndexed' and can I display content by passing $file1_path into search query. Please help