Opt Express. 2023 Apr 24;31(9):14432-14441. doi: 10.1364/OE.487363.
In this paper, we propose a weak measurement method using two pointers to estimate the magneto-optical Kerr angle, which is robust to ellipticity. The double pointers are the amplified displacement shift and intensity of the post-selected light beam, which are the conventional information carried by the light beam and can be directly output by a detector (such as a charge-coupled device). We demonstrate that the product of the double pointers is only related to the phase variation between two basic vectors and independent of the amplitude errors. In the measurement process, when there is an amplitude change or additional amplitude noise between two eigenstates, the product of two pointers is very useful in extracting phase information and shielding amplitude noise. In addition, the product of two pointers has a good linear relationship with the phase variation and a larger dynamic measurement range. This method is applied to measure the magneto-optical Kerr angle of NiFe film. The Kerr angle can be directly obtained using the product of the light intensity and the amplified displacement shift. This scheme is of great significance for the measurement of the Kerr angle of magnetic films.
本文提出了一种使用两个指针进行弱测量的方法来估计磁光克尔角，该方法对椭圆度具有鲁棒性。双指针是经后选的光束的放大位移和强度，它们是光束携带的常规信息，可以直接由探测器（如电荷耦合器件）输出。我们证明，双指针的乘积仅与两个基本向量之间的相位变化有关，与幅度误差无关。在测量过程中，当两个本征态之间存在幅度变化或附加幅度噪声时，两个指针的乘积在提取相位信息和屏蔽幅度噪声方面非常有用。此外，双指针的乘积与相位变化具有良好的线性关系，并且具有更大的动态测量范围。该方法应用于测量 NiFe 薄膜的磁光克尔角。克尔角可以直接通过光强和放大位移的乘积来获得。该方案对于磁性薄膜的克尔角测量具有重要意义。
