difficulty with thank you?

<p>so i have an interview with a duke alum on thursday and i'd really like to send him a thank you letter afterwards (just common courtesy).
ive done this with many interviews, but this time the problem is...
i don't have his email!!! (usually i just email them)</p>

<p>he called me with his cell phone and we arranged to meet via phone.
in this case...how should/would i send a thank you note to him afterwards?</p>

<p>i feel like through text is too casual but asking him for his email during the interview is awkward and weird (if i ask in my super unsmooth fashion)</p>

<p>thanks for the help :)</p>

<p>The admissions office will have his contact information. Contact them and ask for it.</p>