Sending a thank you letter to a research professor? I had an amazing research professor I conducted research under for my last two semesters of undergrad.  I graduated in December and am currently waiting to hear back from graduate programs.  This professor wrote me a letter of recommendation and I sent him a thank you email.  However, I wanted to send him a hand written thank you letter for the letter of recommendation, all I learned while researching under him, and to see how several projects are going since I've graduated and left his lab.  

Is it too late or "awkward" to send him a handwritten thank you note now that it's been about one and a half months since I've last contacted him?
Is it too late or &quot;awkward&quot; to send him a handwritten thank you note now that it's been about two months since I've last contacted him?

Nope.
Two months is not so long in the academic sense at all. Whether or not it's handwritten shouldn't matter as much, either. Typing it up is perfectly acceptable, readable, and much easier to correct if you make an error.