Molecular beam deposition of optical coatings and their characterization

Significant improvements can be made in the fabrication of optical thin film structures by using molecular beam and ultrahigh vacuum techniques. These lead to the achievement of more stable films and multilayer coatings with improved morphology, density, and resistance to laser-induced damage. The microstructure of the film can be controlled to a high degree by using quasisuperlattice techniques, which also provide a means of refractive index synthesis. This can be applied to simple graded structures or complex periodic gradings as required for Bragglike structures. Etalon filters fabricated using the technique have been used for optical bistability experiments and have exhibited stable operation for periods of many hours under continuous cycling.