Is "dabble in" the proper word in this case?
Dabble can have a negative connotation, depending on the circumstances
Take part in an activity in a casual or superficial way: he dabbled in writing as a young man [Oxford Dictionaries Online]
While a person may use the term in a self-deprecating way, even when they have some meaningful measure of skill, in a formal setting the term suggests that your exosure to the alternate field was trivial.
You could simply say something like
While my work has focused on field A, I also have some experience in field B.