Is it common to contact professors you've been in communication with to let them know that you're accepting their school's offer? Do you usually contact the professors that met with you on a campus visit?
Is it usually just a brief FYI type email or a longer/introductory letter? I've already visited campus and spoken to my potential supervisors/advisors.
How does this sound?
Dear Professor L,
I hope all is well. I'm writing to let you know I've accepted School's offer for the PhD program. I am grateful for this opportunity and I look forward to working with you and the rest of the faculty in X Subfield!
Anything I should add?