As an important parameter to determine the transmission characteristics of a Gaussian beam, the beam waist holds a huge impact in laser technology and imaging systems. Although it is necessary to clearly measure the specific value of the beam waist, the traditional measurement steps are complex and easily introduce error in the measurement process. In this work, we propose an effective method using the in-plane spin splitting (IPSS) generated by the photonic spin Hall effect (PSHE) to precisely estimate the beam waist. We establish a highly sensitive propagation model to describe the relationship between the IPSS shifts and the beam waist of an arbitrary linearly polarized light and then combine with the quantum weak measurement system to amplify the IPSS shifts. We reveal that the IPSS shifts are sensitive to the variation of beam waists when the beam is reflected near the Brewster angle. With the huge amplified IPSS shifts (maximum of 1500 microns), the variation of beam waist can be accurately detected, even by propagation amplification alone. Prospectively, our scheme may provide an effective method for accurately determining the Gaussian beam waist of arbitrary polarization.

中文翻译：

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通过面内自旋分裂对任意偏振光束的腰部进行微弱的测量

作为确定高斯光束透射特性的重要参数，束腰对激光技术和成像系统有着巨大的影响。尽管必须清楚地测量束腰的特定值，但是传统的测量步骤很复杂，并且很容易在测量过程中引入误差。在这项工作中，我们提出了一种有效的方法，该方法使用由光子自旋霍尔效应（PSHE）生成的面内自旋分裂（IPSS）来精确估算光束腰围。我们建立了一个高灵敏度的传播模型来描述IPSS位移和任意线性偏振光的束腰之间的关系，然后与量子弱测量系统结合以放大IPSS位移。我们揭示，当光束在布鲁斯特角附近反射时，IPSS位移对光束腰部的变化很敏感。借助巨大的IPSS放大偏移（最大1500微米），即使仅通过传播放大，也可以准确检测到束腰的变化。预期地，我们的方案可以提供一种有效地确定任意极化的高斯光束腰的有效方法。