Abstract

Thermal expansion mismatch between the layers of an optical coating and its substrate can cause changes in the shape of a mirror or optical element. It is shown that with knowledge of the linear stress-temperature relationship for each film, one can design coatings to have a specific thermal deformation characteristic, although the requirements for thin film repeatability are high. Such coatings are demonstrated using atomic layer deposition (ALD), and thermally invariant ALD coatings are investigated through optomechanical simulation.

© 2010 Optical Society of America