[karambahh]

It seems to me that the refractive index plays a role: couldn't you increase resolution by replacing air by another medium every other cut? Say air, water, air, etc.

My reasoning is that you'd increase the resolution without adding too much technical complexity.

My maths is too rusty to evaluate how it would mess with the gray code though.

Very nice idea

[00702]

I didn't include this in my article but I did some experiments early on (for a different idea) with air bubbles in oil inside a Teflon coated tube but that presented a lot of challenges (mainly the bubble breaking up) that made it not ideal for something like this.

This can certainly be miniaturized with the right manufacturing techniques but I left that for the future.