I recently asked this question. The question itself depends on specialist knowledge about laser devices. As you can see in the comments, the user José Andrade said that, by not using the laser tag, a lot of people who are specialists in laser devices, but do not monitor the photonics tag, would miss the question. Furthermore, you can see that I replied that, "based on the tag description for "laser", I thought it seemed more-so for questions about light amplification by stimulated emission (more pure laser questions), rather than photonics (lasers and laser electronics), so I left it out". I am posting this question to seek clarification about when to use the laser tag. What is the proper way to use the laser tag?
My rule of thumb is that more (relevant) tags are better than fewer tags. Every tag that you add puts your question on another list, in front of more other users, and helps the related-question algorithm suggests related questions. You can only have five tags, so feel free to pick the five best ones.
Your question is totally about lasers, so I added that tag (and a couple of others). Feel free to fine-tune further.