Can I publish a critique of an experiment in a field in which I am not an expert?
In order for this to happen, you need two things:


You need to communicate with specialists and convince them that you have identified a logical flaw.  You might worry that they will take your idea without giving you credit, but you shouldn't worry too much about that: the more worrisome scenario is that neither of you will be able to convince the other and it will end with a stalemate.  Without expert advice, it's unlikely that you can present your idea in a way that would be publishable, so talking with experts should be the first step.  (Of course unlikely is different from impossible, but it's best to plan on getting advice.)
Once they understand you, the experts need to care.  Many experiments have loopholes and caveats that are well known to experts but not described in popular accounts or even introductory college courses.  You may end up hearing "Yes, that's logically possible, but it's not a possibility we think is important."  Or "Yes, Jones and Smith pointed that out in a paper last year, but I still think the conclusions are true and the experiment is illuminating."  Using an argument that is not 100% logically air-tight is not in itself a problem outside of pure mathematics.


I'd suggest starting by talking with someone from the course you took (the professor or a teaching assistant).  If all goes well, either you'll convince them that this is new and serious, or they'll convince you that it isn't.