Notes:

Unfortunately, the recording computer crashed due to overheating during the lecture on Friday, 06.11.2020, and as a result the video recording is broken. As a substitute, we provide recordings from a previous semester (when there was no obligation to wear masks).

Note that this year the enumeration of the chapters is a bit different:
§2. Propagation of waves in optical media
$3. Gaussian Rays/Beams