Abstract
Free carrier generation due to the presence of absorbing contaminants is considered as a primary mechanism for initiating continuous-wave laser damage in low absorption, high bandgap optical coatings. Thermal, optical, and ion-generation are examined as means of exciting electrons above the bandgap of the material. Once electrons exist above the bandgap, they absorb incident light, causing a runway thermal-Absorption process leading to material breakdown. Testing this theory, high reflectivity distributed Bragg reflectors and half-wave coatings were tested with a 17kW 1070nm continuous wave laser in the presence of carbon contamination. Damage thresholds of titania, tantala, hafnia, alumina, and silica were compared to theory and found to follow similar trends. In an effort to prevent laser damage, samples were conditioned using lower irradiance levels, prior to higher exposure. This was found to reduce absorption by up to 90% as well as increase damage thresholds by over an order of magnitude for some samples.
Original language | English (US) |
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Title of host publication | 2016 IEEE Photonics Conference, IPC 2016 |
Publisher | Institute of Electrical and Electronics Engineers Inc. |
Pages | 462-463 |
Number of pages | 2 |
ISBN (Electronic) | 9781509019069 |
DOIs | |
State | Published - Jan 23 2017 |
Event | 29th IEEE Photonics Conference, IPC 2016 - Waikoloa, United States Duration: Oct 2 2016 → Oct 6 2016 |
Publication series
Name | 2016 IEEE Photonics Conference, IPC 2016 |
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Other
Other | 29th IEEE Photonics Conference, IPC 2016 |
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Country/Territory | United States |
City | Waikoloa |
Period | 10/2/16 → 10/6/16 |
Bibliographical note
Publisher Copyright:© 2016 IEEE.