Sushkov A O, Williams E, Yashchuk V V, Budker D, Lamoreaux S K
Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA.
Phys Rev Lett. 2004 Oct 8;93(15):153003. doi: 10.1103/PhysRevLett.93.153003. Epub 2004 Oct 6.
The electro-optical Kerr effect induced by a slowly varying electric field in liquid helium at temperatures below the lambda point is investigated. The Kerr constant of liquid helium is measured to be (1.43+/-0.02(stat)+/-0.04(sys)) x 10(-20) (cm/V)(2) at T=1.5 K. Within experimental uncertainty, the Kerr constant is independent of temperature in the range T=1.5 K to 2.17 K, which implies that the Kerr constant of the superfluid component of liquid helium is the same as that of normal liquid helium. Pair and higher correlations of He atoms in the liquid phase account for about 23% of the measured Kerr constant. Liquid nitrogen was used to test the experimental setup; the result for the liquid nitrogen Kerr constant is (4.38+/-0.15) x 10(-18) (cm/V)(2). Kerr effect can be used as a noncontact technique for measuring the magnitude and mapping out the distribution of electric fields inside these cryogenic insulants.
研究了在低于λ点的温度下，缓慢变化的电场在液氦中引起的电光克尔效应。在T = 1.5 K时，测得液氦的克尔常数为(1.43±0.02(统计误差)±0.04(系统误差))×10^(-20) (cm/V)^2。在实验误差范围内，克尔常数在T = 1.5 K至2.17 K的范围内与温度无关，这意味着液氦超流成分的克尔常数与正常液氦的克尔常数相同。液相中氦原子的对关联和更高阶关联约占测得克尔常数的23%。使用液氮来测试实验装置；液氮克尔常数的结果为(4.38±0.15)×10^(-18) (cm/V)^2。克尔效应可用作一种非接触技术，用于测量这些低温绝缘体内部电场的大小并绘制电场分布。
