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In this video, I talk about where the band diagrams we have been using to this point fall short, and how band structure (or E/k diagrams) are much more useful when dealing with optical transitions. This band structure will allow us to use what we have learned about two-level systems and apply it to figure out the absorption spectrum of a semiconductor.

This is part of my graduate series on optoelectronics / photonics, and is based primarily on Coldren's book on Lasers as well as graduate-level coursework I have taken in the EECS department at UC Berkeley.

Hope you found this video helpful, please post in the comments below anything I can do to improve future videos, or suggestions you have for future videos.