TY - JOUR
T1 - The effect of temperature on the absorption coefficient of water for holmium
T2 - Laser Interaction with Hard and Soft Tissue 1993
AU - Jansen, E. Duco
AU - Van Leeuwen, Ton G.
AU - Motamedi, Massoud
AU - Borst, C.
AU - Welch, A. J.
N1 - Funding Information:
The authors gratefully acknowledge the support of the Office of Naval Research (grant N00014-91-J-1564), the Albert and Clemmie Caster Foundation, the Netherlands Heart Foundation (grant 37.007) and the National Science Foundation (grant BCS-91 10257). We also like to thank Dr. Ed Sinofsky of Rare Earth Medical, Inc. for his advice concerning the JR lasers.
Publisher Copyright:
© 1994 SPIE. All rights reserved.
PY - 1994/2/1
Y1 - 1994/2/1
N2 - The dynamics of the water absorption peak around 1.94 μm was examined. This peak is important for the absorption of holmium and thulium laser radiation. To examine the effect of temperature on the absorption coefficient, the transmission of light through water of 22, 49 and 70 °C was measured from 1850-2150 nm with a spectrophotometer. It was found that the absorption peak at 1.94 μm (at 22 °C) shifts to shorter wavelengths with increasing temperatures, to 1.92 μm at 70 °C. It was also seen that the absorption peak increases slightly with increasing temperature. Secondly, a pulsed Ho:YAG laser (λ =2.12 μm) was coupled into a 600 μm low OH fiber (pulse duration 200μs, radiant exposure 70.7 mJ/mm2). The transmission was measured as a function of the thickness of the water layer at 22,49 and 70 °C. It was found that the absorption coefficient at this wavelength decreases with increasing temperature. A finite difference model was developed to predict the temperature distribution due to a single Holmium:YAG laser pulse incorporating the dynamic change in absorpüon coefficient with temperature that was measured with the spectrophotometer. The temperature distributions are compared to the predictions of a model assuming constant optical properties. It is shown in this paper that the dynamics of the absorption coefficient has a significant influence on the expected zone of damage and ablation parameters in the 2 μm wavelength range.
AB - The dynamics of the water absorption peak around 1.94 μm was examined. This peak is important for the absorption of holmium and thulium laser radiation. To examine the effect of temperature on the absorption coefficient, the transmission of light through water of 22, 49 and 70 °C was measured from 1850-2150 nm with a spectrophotometer. It was found that the absorption peak at 1.94 μm (at 22 °C) shifts to shorter wavelengths with increasing temperatures, to 1.92 μm at 70 °C. It was also seen that the absorption peak increases slightly with increasing temperature. Secondly, a pulsed Ho:YAG laser (λ =2.12 μm) was coupled into a 600 μm low OH fiber (pulse duration 200μs, radiant exposure 70.7 mJ/mm2). The transmission was measured as a function of the thickness of the water layer at 22,49 and 70 °C. It was found that the absorption coefficient at this wavelength decreases with increasing temperature. A finite difference model was developed to predict the temperature distribution due to a single Holmium:YAG laser pulse incorporating the dynamic change in absorpüon coefficient with temperature that was measured with the spectrophotometer. The temperature distributions are compared to the predictions of a model assuming constant optical properties. It is shown in this paper that the dynamics of the absorption coefficient has a significant influence on the expected zone of damage and ablation parameters in the 2 μm wavelength range.
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U2 - 10.1117/12.168029
DO - 10.1117/12.168029
M3 - Conference article
AN - SCOPUS:0005290934
VL - 2077
SP - 195
EP - 201
JO - Proceedings of SPIE - The International Society for Optical Engineering
JF - Proceedings of SPIE - The International Society for Optical Engineering
SN - 0277-786X
Y2 - 29 August 1993 through 3 September 1993
ER -