Dynamics of refractive index variation in diamond crystal during and after its irradiation by fs laser pulses has been investigated by the pump-probe interferometric technique. It is found that, as well as the positive + Δn variation of refractive index determined by the Kerr effect and the negative -Δn resulting from bulk ionization, there is a positive +Δn determined by material heating. Analysis of experimental data and modeling allows us to visualize a laser heated volume, to trace its growth in time and to determine the temperature of material in the beam waist. The maximum observed temperature for intensity ≈3 × 10~(12) W cm~(-2) is estimated as 700 K.
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机译：通过泵浦探针干涉技术研究了金刚石晶体在被fs激光脉冲照射期间和之后的折射率变化动力学。发现，除了由克尔效应确定的折射率的正+Δn变化和由本体电离导致的负的-Δn变化之外，还有由材料加热确定的正+Δn。通过对实验数据和模型的分析，我们可以可视化激光加热的体积，追踪其随时间的增长并确定光束腰中材料的温度。强度≈3×10〜（12）W cm〜（-2）的最高观测温度估计为700 K.
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