TY - GEN
T1 - Contamination mediated continuous-wave laser damage of optical materials
AU - Brown, Andrew
AU - Ogloza, Albert
AU - Olson, Kyle
AU - Talghader, Joseph
PY - 2017/1/23
Y1 - 2017/1/23
N2 - 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.
AB - 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.
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U2 - 10.1109/IPCon.2016.7831178
DO - 10.1109/IPCon.2016.7831178
M3 - Conference contribution
AN - SCOPUS:85014228692
T3 - 2016 IEEE Photonics Conference, IPC 2016
SP - 462
EP - 463
BT - 2016 IEEE Photonics Conference, IPC 2016
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 29th IEEE Photonics Conference, IPC 2016
Y2 - 2 October 2016 through 6 October 2016
ER -