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open access

Investigation of the microstructure of coatings for high power lasers by non-optical techniques

Description: The microstructure of optical coatings strongly influence their resistance to high fluence laser, scatter properties, as well as, their mechanical and environmental stability. The relative merits of non-optical techniques, such as: scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and focused ion beam, are discussed as they apply to optical multilayer coatings. The combination of these techniques provides a unique method to analyze defects in coatings. The… more
Date: June 1, 1994
Creator: Tench, R. J.; Kozlowski, M. R. & Chow, R.
Partner: UNT Libraries Government Documents Department
open access

Defect geometries and laser-induced damage in multilayer coatings

Description: A correlation between laser-induced damage and the height of a coating defect was found from an examination of HfO{sub 2}/SiO{sub 2} mirrors made by three different coating vendors. The nodular defects in these reactive e-beam deposited mirrors were studied using the combination of SEM, optical microscopy, FIB and AFM techniques. Each vendor had small defects in common, but characteristically different large defects. Also the majority of seeds that caused the defects were made of hafnia, not si… more
Date: July 1, 1994
Creator: Tench, R. J.; Kozlowski, M. R. & Chow, R.
Partner: UNT Libraries Government Documents Department
open access

Characterization of defect geometries in multilayer optical coatings

Description: Laser-induced damage in optical coatings is generally associated with micrometer-scale defects. A simple geometric model for nodule-shaped defects is commonly used to describe defects in optical coatings. No systematic study has been done, however, to prove the applicability of that model to standard optical coating deposition. Some defects are known not to have a classic nodule geometry. The present study uses atomic force microscopy (AFM) and scanning electron microscopy to characterize the t… more
Date: December 1, 1993
Creator: Tench, R. J.; Chow, R. & Kozlowski, M. R.
Partner: UNT Libraries Government Documents Department
open access

Influence of defect shape on laser-induced damage in multilayer coatings

Description: Atomic force microscopy (AFM) was used as a diagnostic for laser damage testing of lim-scale nodule defects in e-beam deposited HfO2/SiO{sub 2} multilayer mirror coatings. Earlier experiments in our laboratory showed that there was a significant increase in damage susceptibility for defects with heights greater than 0.6 {mu}m. In the present study, e-beam HfO{sub 2}/SiO{sub 2} HR coatings from two additional vendors were also studied. Atomic force microscopy characterization of the defects show… more
Date: June 1, 1994
Creator: Kozlowski, M. R.; Tench, R. J.; Chow, R. & Sheehan, L.
Partner: UNT Libraries Government Documents Department
open access

A comparison of nodular defect seed geometeries from different deposition techniques

Description: A focused ion-beam milling instrument commonly utilized in the semiconductor industry for failure analysis and IC repair, is capable of cross-sectioning nodular defects. Utilizing the instrument`s scanning on beam, high-resolution imaging of the seeds that initiate nodular defect growth is possible. In an attempt to understand the origins of these seeds, HfO{sub 2}/SiO{sub 2} and Ta{sub 2}O{sub 5}/SiO{sub 2} coatings were prepared by a variety of coating vendors and different deposition process… more
Date: December 29, 1995
Creator: Stolz, C. J.; Tench, R. J.; Kozlowski, M. R. & Fornier, A.
Partner: UNT Libraries Government Documents Department
open access

Optical properties of silicon clusters deposited on the basal plane of graphite

Description: Laser ablation was used to deposit of silicon on highly oriented pyrolytic graphite surfaces in an ultra high-vacuum environment equipped with Auger electron spectroscopy (AES), scanning tunneling microscopy (STM) and luminescence spectroscopy. For deposition of up to several monolayers, post annealing produced silicon clusters, whose size distribution was determined vs annealing time and temperature using STM. Pure silicon clusters ranging from 1 to 10 nm showed no detectable photoluminescence… more
Date: April 1, 1994
Creator: Dinh, L. N.; Chase, L. L.; Balooch, M.; Terminello, L. J.; Tench, R. J. & Wooten, F.
Partner: UNT Libraries Government Documents Department
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