Contamination mediated continuous-wave laser damage of optical materials
| Autor: | Joseph J. Talghader, Kyle D. Olson, Albert Ogloza, Andrew Brown |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Materials science biology business.industry Band gap Hafnia biology.organism_classification 01 natural sciences Ray 010309 optics 03 medical and health sciences 030104 developmental biology Optics Optical coating 0103 physical sciences Optoelectronics Continuous wave business Absorption (electromagnetic radiation) Order of magnitude Photonic crystal |
| Zdroj: | 2016 IEEE Photonics Conference (IPC). |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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