ABSTRACT
49Don’t be afraid to ask questions. When I taught coherence theory most of my students were engineers and I discovered that some of them did not actually understand the essence of correlation, although some of them used the correlation function. Added to that, some of the engineers did not actually know the meaning of, and basic distinction between, coherence and correlation. This was because coherence theory was developed by optical physicists (a whole different field from engineering). In my effort to help students understand (i.e., cognitive learning) the coherence theory of light, I usually started with a simple example as seen below. If you are able to grasp this simple illustration you will have a better fundamental mastery of the subject than many of my PhD students!
