There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. (arxiv.org)
As Roland Terborg comments, «The challenge of developing a lens - free microscope to detect single protein layers (less than 1nm of optical path difference) seemed rather difficult at the beginning. (sciencedaily.com)
This telescope will be ideal for coronagraphy and other techniques requiring stable optical path as it will be seeing limited with very low instrumental scattered light. (planets.life)