<p>This summer and part-time next year I am interning at a prominent research facility. Would it be beneficial to my application to submit a recommendation from my post doc? If so, how much would this help?</p>
<p>If you think that it really adds a side to you that your other teachers won't include, then it's fine. Colleges generally prefer two letters, because they don't like reading much more than they have to.</p>