Effect of hydrogen concentration in conventional and IAD coatings on the absorption and laser-induced damage at 10.6 μm

Abstract

Various properties of optical coatings are sensitive to the concentration of hydrogen in the constituent layers. Especially water, OH-compounds or hydrocarbons adsorbed by the layers have a dominant influence on the absorption, and on the laser induced -damage behavior at 10.6 pm.In this paper, data of single layers of YbF3, BaF2, YF3 and NaF and multilayer coatings produced by conventional thermal evaporation (boat, e-beam) and ion assisted deposition (lAD) are compared.Hydrogen concentration depth profiling was performed using nuclear reaction analysis based on the reaction 1H(1N, cry)12C. Absorption was measured with the aid of a laser calorimeter and a cw CO2 laser. A computer -controlled test facility with a TEA CO2 laser was used for determining the 1-on-I damage thresholds of the coatings.The results point out that the absorption and damage behavior of coatings for the CO laser wavelength are related to the total amount of species containing hydrogen. Most of the lAD coatings exhibit a lower hydrogen contamination than conventional thin films.

High-Strength Optical Coatings for Single-Crystal ZnGeP2 by the IBS Method Using Selenide and Oxide Materials

“…For example, in [23], it is shown that its LIDT is in the range of 1-3 J/cm 2 , at a pulse repetition rate of 1 Hz. At the same time, in [24], an AR coating based on a ZnSe/YbF 3 pair shows LIDT at a level of 12.2 J/cm 2 . Additionally, ZnSe/YbF 3 structures on CaF 2 substrates by the e-beam evaporation method obtained Bloch surface waves [25] and deformable mirrors [26].…”

Influence of the number of double layers on the damage threshold of Al 2 O 3 /SiO 2 and LaF 3 /MgF 2 mirrors at 248 nm

“…2) were deposited on substrates from the same batches under standard purity conditions as can be attained with oil diffusion pumps. In order to optimize the microstructure of the coatings [16,17], a substrate temperature in excess of 400°C was chosen. The major difference between these two batches was the evaporation process: coating materials were evaporated from thermal boats for batch A and from electron beam evaporators for batch B.…”

Properties of the YbF3 Films Prepared by Ion-Assisted Deposition

“…YbF 3 is an important multispectral optical film with low optical loss, good mechanical properties and good environmental adaptability [1], which has been widely used in highperformance antireflection films [2][3][4][5], high-reflection mirrors [6], high-power infrared laser films [7][8][9] and high-efficiency beamsplitters [10,11].…”