The course content is good. But the instructors had not been responsive to any question posted on the forum.

The content is good, and the instructor is very responsive through email. Though I think the capstone is not as challenging as the first course.

The lab demonstrations were very helpful and the explanations of complex phenomena were very easy to understand.

This is a great course, it covers a lot of important topics with elegant explanation and impressive lab demonstrations. The homeworks are challenging, and one may usually find it very difficult at the first try, but most of them can be solved with educational return thanks to these inspiring discussion thread in responsive forum.

However, I think I have to remove one star because of the difficulty of using trial version of Zemax for capstone. The absence of saving function and stability issue (it crashes often!) make it very painful to use; you need to input ~20-30 parameters to model the system correctly, and then all in sudden a crash happens and you have to start over from zero, ouch! I would recommend other alternatives like OSLO or WinLens for the future update of this course since the concept is the same. By the way, I think there should be a filter in the course forum or it gets flooded by the recurring lecture-related posts very quickly.

I loved the first course in this specialization, but this one was disappointing. Quizzes are often not precise enough in what is required as an input, so I wasted too much time on finding out how to format my answers so that grading system accepts them.

Zero response from any of the course moderators in the forums.

Strict theoretical concepts are explained nicely, but course lacks more examples of application to bridge the gap towards skills needed in homeworks.

The course did offer directions which I can use afterwards to continue to learn on my own, and I count that as a valuable thing.