I have a distant childhood memory of a book based on this concept, in which the protagonist is projected back in time through light beams bounced off of distant

I have a distant childhood memory of a book based on this concept, in which the protagonist is projected back in time through light beams bounced off of distant mirrors. I think I stopped reading because I could tell the science was completely impossible, and ultimately just an excuse to write an historical fiction book which I didn't feel like reading. Perhaps I judged it too harshly?