I was asked by a talmid of mine who is in college, whether he can use notes taken on Shabbos or Yom Tov by a non-religious Jewish friend?
There are various opinions from the Tannaim down through the poskim on the extent of the prohibition of ma’aseh Shabbat, things produced through the violation of Shabbat (see Ketubot 34a). Rabbi Meir says that if Shabbat was violated by mistake, it is permitted to use the result even on Shabbat; if it was done on purpose, it is forbidden for the perpetrator but permitted for others. According to Rabbi Yehuda, even by mistake, it is forbidden for everyone on Shabbat but permitted after Shabbat for those other than the perpetrator. (There is a third, more stringent opinion, which is not accepted as halacha.) The Shulchan Aruch (Orach Chayim 318:1), following the Rif and Rambam, rules like Rabbi Yehuda. The Gra, like Tosafot before him, rules like the lenient Rabbi Meir. The Mishna Berura (318:7) says that one can rely on the lenient opinion regarding shogeg (that it is permitted for all on Shabbat). In any case, since your talmid is not the perpetrator, it seems clear that it is permitted for him, as all the normative opinions agree that it is permitted for others after Shabbat.
However, there are a few issues to deal with. First, there are opinions that even others need to wait bichdei sheya’asu (the amount of time it would take to get the result if one started after Shabbat). This concept is found regarding a non-Jew who did work on behalf of a Jew. This waiting period is still required even though the non-Jew did nothing wrong and even in cases where the Jew did not improperly tell him to do so (Beitza 24b). Two possible reasons are advanced for this halacha. Rashi (ad loc.) says that it is in order to not benefit from work done on Shabbat. Tosafot says that it is so one not come to ask the non-Jew to do work. The Pri Megadim (Eshel Avraham 225:22) reasons that the issue of benefiting from work on Shabbat should apply to a Jew who regularly violates Shabbat. However, regarding Tosafot’s reason, we do not expect a religious Jew to ask a Shabbat desecrator to do work on Shabbat. The Mishna Berura adds a reason not to say bichdei sheya’asu regarding a Jew – a Jew will not listen to a request to do melacha, and one can argue that this does not apply to those who regularly violate Shabbat (see our Bemareh Habazak I:31). The Pri Megadim leaves the matter unresolved, and there is not a consensus among contemporary poskim (see ibid., where we leaned toward leniency, and Orchot Shabbat 25:(25), who leans toward stringency).
How long would bichdei sheya’asu be in our case? On the one hand, if the student did not take notes at the time of the class, he would not have them, and thus maybe it is forever. However, logic dictates that the information could still be obtained from another student, and it would not take long. Therefore, even if one were to be stringent regarding bichdei sheya’asu, he could take the notes relatively soon after Shabbat.
If the note taker takes money for using his notes, paying him might be forbidden (see Shut K’tav Sofer, OC 50). We will curtail discussion of this point, with the assumption that this is not the case here.
While according to pure halacha, it is permitted to use the notes, there is a preference to use a non-Jew’s notes for the following reason. There is an element of chillul Hashem in taking advantage of chillul Shabbat in a manner that includes personal interaction. It can be seen (to your talmid and/or to his classmate) as if he is saying: “I can’t come to class, but I am glad you are there to help me out.” The aforementioned responsa in Bemareh Habazak rules that it is permitted to take a ride from shul on Motzaei Shabbat with one who drove his car there on Shabbat. However, we said (see also Tzitz Eliezer XIII:48) that it is improper to do so on a regular basis for the above reason. The appropriate level of sensitivity in this regard depends on the people involved and cannot be fully captured in this forum.