…here is how you can do that using spiraling beams. In our recent work, which is now published in Applied Optics, we show you can measure the distance with a precision of 2 µm over a range of 2 mm! And apparently we are not the only one that think our method interesting, because the editors also highlighted it as an Editors’ Pick! You can find more information here.
Congrats to Shashi, Stephen and all co-authors for this nice demonstration!