People sometimes use archaic terms. But as you can see with the Ngram viewer, quadroon is rare, and I suspect it mostly appears now in historical works.

https://books.google.com/ngrams/graph?content=quadroon&year_start=1800&year_end=2019&corpus=26&smoothing=3&direct_url=t1%3B%2Cquadroon%3B%2Cc0