What are the reasons why optics is difficult to learn in college advanced physics?

There are many reasons why optics is difficult to learn in college advanced physics, some of which may be:

1. Optics involves many concepts and needs to master many formulas, which may make beginners feel difficult.

2. Some concepts in optics are abstract, such as the fluctuation and particle nature of light, which may confuse beginners.

3. Some experiments in optics are complicated, such as interferometer and diffractometer, which may require some skills and experience to complete.