#4 is really nice; light moving at different speeds in different media. I'm also struck by #2, light reflecting off a mirror, because some of the photons apparently carry on through the mirror (he said, as if recording the main packet bouncing off it were no big deal...).

In the near term, could this technology lead to to the development of improved beam splitters, mirrors, bottles etc. that would drive the development of optical computing?

Quoting the caption from figure 3 in the article:

"The bright spot behind the mirror is attributed to imperfect resolution."