Estimation of the Refractive Index Change in Glass Induced by Femtosecond Laser Pulses
Estimation of the Refractive Index Change in Glass Induced by Femtosecond Laser Pulses
复制标题
飞秒激光脉冲引起的玻璃折射率变化的估计
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
K. Hayashi
中科院分区：
文献类型：
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作者：
T. Toma;Y. Furuya;W. Watanabe;K. Itoh;J. Nishii;K. Hayashi
众所周知，当具有极高高峰功率的飞秒激光脉冲发射到玻璃中时，会发生局部折射率变化。我们将800 nm的130飞秒激光脉冲聚焦到玻璃体中，并检查了诱导折射率变化的形状。我们发现，尽管直径约为2 μm，但折射率沿光轴沿着变化的光斑长度达到约30 μm。为了估计诱导折射率变化的分布，我们通过扫描聚焦光斑来制作布拉格光栅，并通过将Kogelnik的耦合模理论应用于高阶衍射光束的测量衍射效率来计算变化量。
It is known that local refractive index change occurs when femtosecond laser pulses with extremely high peak power are launched into glass. We focused 130-femtosecond laser pulses of 800 nm into the bulk of glass and examined the shape of the induced refractive index change. We found that the length of the spot of the refractive index change along the optical axis reached about 30 μm despite the diameter being about 2 μm. To estimate the distribution of induced refractive index change, we fabricated Bragg grating by scanning the focused spot and calculated the amount of the change by applying Kogelnik’s coupled mode theory to the measured diffraction efficiencies of the higher order diffracted beams.