Even so, ~1 atmosphere for a gap that is order-of-magnitude comparable to current technology is interesting, and higher than I would have guessed. On reflection

Even so, ~1 atmosphere for a gap that is order-of-magnitude comparable to current technology is interesting, and higher than I would have guessed. On reflection, there's a correspondence between the frequency of the light needed in fabricating features of this size by photolithography, and the cut-off frequency for the Casimir effect in those features.