Laser deposition and characterization of optical layers

In this work is presented study of optical properties of the HfO2, LaF3, Al2O3, CeO2, Yttrium-stabilized ZrO2 deposited by Pulsed Laser Deposition. The results were compared with magnetron sputtered Al2O3 and Ta2O5. The experimental arrangement consists of the KrF excimer laser and stainless-steel chamber where the rotating target and heated substrate holder are placed. The laser beam is focused by the lens onto the target of required material The films were deposited on fused silica substrate (Suprasil). For correct stoichiometry, the oxide films were deposited in oxygen atmosphere. The films were studied by spectroscopy in the UV-Visible and infrared ranges and by spectroscopic ellipsometry. The ellipsometric real-time procedure was used to characterize thin films and for the detection of possible changes on the samples induced by high-power radiation. Al2O3 coatings deposited by magnetron sputtering had porosity degrees of 14%. The fraction of pores was calculated by Bruggeman model of effective media. PLD-deposited Al2O3 was more compact. However, this film possessed inhomogenious refractive index profile. Some films deposited by PLD (especially fluorides) possess high absorption background caused by small particles on the surface that originate from deposition process. The multilayer structure Ta2O5 were deposited without breaking vacuum due to multitarget carousel. One was made by two films Ta2O5 and the other coating was made by five couples of Ta2O5. Absorption on the interfaces between the layers was studied on these multilayers. Copyright © 1998 by MANK Hay?a/Interperiodica Publishing.