10 December 2001 Measuring small absorption losses of laser pulses in fused silica by a pump and probe technique
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A compact experimental setup, based on the laser induced deflection technique (LID), measures small absorption coefficients in fused silica upon 193-nm irradiation with high sensitivity and accuracy. For that, two probe laser beams are passed numerous times through a sample and are deflected by a refractive index gradient which is generated by the power absorbed within the material. The absorption coefficient of the sample is determined by applying a comfortable and precise electrical calibration procedure. The investigation of two equivalent fused silica samples of different thickness confirmed that the setup allows to exclusively measure the bulk absorption of the material without contributions from the irradiated surfaces. Furthermore, influences of irradiation parameters like repetition rate and pulse width on the absorption coefficient of fused silica at a fixed applied energy density have been investigated. The results confirm the complexity of the absorption mechanism present in fused silica upon laser irradiation. In order to separate linear and nonlinear absorption two fused silica samples have been irradiated with different energy densities keeping the repetition rate and the pulse width constant. The results show a nonlinear dependence of the absorption coefficient on the energy density which can qualitatively be explained by the two-step absorption mechanism in fused silica.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Christian Muehlig, Christian Muehlig, Siegfried Kufert, Siegfried Kufert, Sylvia Bark-Zollmann, Sylvia Bark-Zollmann, Wolfgang Triebel, Wolfgang Triebel, } "Measuring small absorption losses of laser pulses in fused silica by a pump and probe technique", Proc. SPIE 4449, Optical Metrology Roadmap for the Semiconductor, Optical, and Data Storage Industries II, (10 December 2001); doi: 10.1117/12.450100; https://doi.org/10.1117/12.450100

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