Search results for "Angular dispersion"
showing 2 items of 2 documents
In-situ diagnostic of ultrashort probes based on Kerr-index transient Bragg grating
2019
Pump-probe experiments are essential tools to investigate ultrafast dynamics of laser-matter interaction. We are particularly interested in the dynamics of transparent dielectrics under high numerical aperture focusing. Two main challenges arise for the weak probe pulse. First, we need a precise knowledge of the probe delay with respect to the pump pulse. Second, dispersion compensation of the ultrashort probe pulse generally requires a prism compressor, which can generate angular dispersion, and therefore incorrect interpretation of the pumpprobe measurements.
Raman spectroscopy study of β-irradiated silica glass
2003
International audience; Natural and synthetic silica glass samples with different OH content have been submitted to β-irradiation at different doses from 106 to 5 × 109 Gy in a Van de Graaff accelerator. Structural changes under irradiation have been analyzed by Raman spectroscopy. The main findings are: (i) a decrease of the Si–O–Si angular dispersion and the average Si–O–Si angle as a function of dose and (ii) an increase of number of three-membered SiO4 ring concentration during irradiation. These results show therefore that purely electronic excitation from β-irradiation induces in a-SiO2 small but significant structural changes of the SiO4 membered ring statistics (size and dispersion)…