Regensburg 2007 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 11: Poster Session

DF 11.16: Poster

Thursday, March 29, 2007, 14:30–18:00, Poster C

Topographic investigation of IR-, VIS- and UV-induced damages on LiB₃O₅ surfaces by low coherence microscopy — •Änne Andresen, Stefan Möller, and Mirco Imlau — Department of Physics, University of Osnabrück, D-49069 Osnabrück

The topographic development of IR-, VIS- and UV-induced damages on the output surfaces of LiB₃O₅ (LBO) crystals has been investigated by low coherence microscopy (LCM) as a function of exposure. The surface damages were caused during long-term exposure with a focussed beam of a Q-switched Nd:YAG laser at wavelengths of 1064, 532 and 355 nm, a repetition rate of 20 kHz, pulse lengths of 10 ns, an average power of P_1064 nm = 1.5 W and a beam waist of 20 µm. The LCM-method enabled us to distinguish between deposition and ablation processes on the LBO surface with an accuracy of up to 1 nm in z-direction. Additionally, the influence of the single wavelengths as well as the mixing of two and three wavelengths on the damage formation can be estimated. The results are interpreted in the frame of surface damage formation during sum-frequency generation in LBO crystals. The particular role of ambient atoms and surface polishing procedures for the damage formation is discussed. Financial support of the Deutsche Forschungsgemeinschaft (TFB 13-04, GRK 695) is gratefully acknowledged.