Refractive index of [100] lithium fluoride under shock pressures up to 151 GPa
Refractive index of [100] lithium fluoride under shock pressures up to 151 GPa
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DOI：
10.1063/1.5065543
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发表时间：
2018-12
期刊：
影响因子：
1.6
通讯作者：
G. Young;Xun Liu;C. Leng;Jun Yang;Haijun Huang
中科院分区：
文献类型：
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作者：
G. Young;Xun Liu;C. Leng;Jun Yang;Haijun Huang
单晶氟化锂（LiF）是冲击波实验中广泛使用的窗口材料，用于保持样品表面的冲击应力。它在高达200 GPa的冲击压缩下是透明的，允许干涉仪记录被监测表面的运动。然而，干涉仪技术需要知道在冲击压缩下LiF的准确折射率来推导真实的粒子速度。虽然LiF在冲击压缩下的折射率已经研究了很长时间，但不同的实验结果存在分歧，特别是在高压区域。在这里，我们使用铁作为标准物质，使用两级轻气枪测量[100] LiF的折射率高达151 GPa。结果表明，在1550 nm光下，当粒子表观速度uapp > 0.38 km/s时，粒子真速度utrue与粒子表观速度uapp呈线性关系，utrue = 12.26（2.07）m/s + 0.7759（0.0005）uapp。
Single-crystal lithium fluoride(LiF) is a widely used window material in shock wave experiments to maintain the shock stress on the sample surface. It is transparent under shock compression up to ∼200 GPa, allowing the interferometer to record the movement of the monitored surface. However, the interferometer techniques require knowing the accurate refractive index of LiF under shock compression to deduce the true particle velocity. Although the refractive index of LiF under shock compression has long been studied, different experimental results diverge, especially in the high pressure region. Here, we used iron as the standard material to measure the refractive index of [100] LiF up to 151 GPa using two-stage light gas gun. Our results show that for the 1550 nm light, the true particle velocity (utrue) has a linear dependence on the apparent particle velocity (uapp), utrue = 12.26(2.07)m/s + 0.7759(0.0005)uapp, when the apparent particle velocity, uapp > 0.38 km/s.