SEDL / STP / STP954-EB / STP23131S

Interface and Bulk Absorption of Oxide Layers and Correlation to Damage Threshold at 1.06 μm

Ristau, D
Universität Hannover,

Dang, XC
Universität Hannover,

Ebert, J
Universität Hannover,

Pages: 15    Published: Jan 1986

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Abstract

We describe an infrared line scanning technique for measuring the temporal and spatial development of a temperature field which is generated by a high power cw Nd-laser on the surface of a coated sample. A theoretical model based on the solution of the differential equation of heat transport for an instantaneous point source is discussed. In this theory the optical and thermal properties of a laser heated single layer are related to its temperature field. Investigations on a temperature calibration technique are made in order to rule out the effect of different emissivities of the coating materials under test. In the present study interface and bulk absorption of single layers and multilayer stacks are measured and related to the laser damage threshold attained from 15 ns pulses at 1.064 μm. The layers are produced by e-beam evaporation and by ion-beam assisted deposition. Results will be given on TiO², Ta²O⁵, HfO², Al²O³ and SiO².