Protecting a directory

I hope this is the appropriate place for this post - I apologize in advance if I'm stepping on any toes... I have created a database to manage my contacts in a sub-directory of my site. I used php user authentication to protect the directory, but you can still see the directory index by entering "http://www.somefakeurl.com/admin/. Since i do not want to use an index page in that directory, is there any way to keep people from seeing that index using PHP? Thank you Tom