Mechanical Stress in Optical Coatings

Optical and mechanical properties of thin RLVIP Nb 2 O 5 -films

“…By using a laser interferometric technique (Tencor FLX-2320 at Fraunhofer Institute of Applied Optics and Precision Engineering IOF) the curvature of each disc-shaped Si-substrate was determined before and after deposition. Knowing the elastic data of silicon and the thickness of the disc the mechanical film stress was calculated [6]. Although in a constrained amorphous state, RLVIP-metal-oxide-films are nearly stable in their properties.…”

“…Mechanical film stress is influenced by particle energy, deposition rate, film thickness and physical or chemical incorporation of material [6]. In this case for the first series of experiments the mechanical film stress depending on the arc current was investigated.…”

Production of Optical Coatings Resistant to Damage by Petawatt Class Laser Pulses

“…Thus, lowering or raising the temperature can change the dynamics at the molecular level by which coatings form. In particular, coating at an elevated temperature of ~ 200 o C can promote formation of coatings with mechanical stress (Strauss, 2003) that matches or is close to that of the substrate. This is important because stress differences between a coating and substrate increase the risk of the coating delaminating from the substrate.…”

High-performance thin-film optical filters with stress compensation

“…With these energetic technologies, very dense layers are produced. As a consequence, the produced coatings are more and more resistant in harsh conditions but high residual stress is then generally observed in the layers [1]. In most of the coatings produced with oxide materials, this high residual stress is generally not a problem from an adhesion point of view (delamination can generally be avoided by combining the proper materials), but it can induce large substrate deformation that scale with the substrate diameter and the square of the thickness of the substrate [2,3].…”