Baishya Upasana, Kumar Nitish, Viswanathan Nirmal K
Opt Lett. 2022 Sep 1;47(17):4479-4482. doi: 10.1364/OL.468088.
While an optical system's symmetry ensures that the spin Hall effect of light (SHEL) vanishes at normal incidence, the question of how close to the normal incidence can one reliably measure the SHEL remains open. Here we report simulation and experimental results on the measurement of SHEL at $\sim 0.12^\circ$ away from normal incidence in the Fourier plane of a weakly focused beam of light, reflected at an air-glass interface. Measurement of transverse spin-shift due to $< 0.05^\circ$ polarization variation in the beam cross section along the X- and Y-directions is achieved in the dark-field region of the reflected beam. Our ability to measure the SHEL at near-normal incidence with no moving optomechanical parts and significantly improved sensitivity to phase-polarization variations is expected to enable several applications in the retro-reflection geometry including material characterization with significant advantages.
虽然光学系统的对称性确保了光的自旋霍尔效应（SHEL）在正入射时消失，但人们能在多接近正入射的情况下可靠地测量SHEL这个问题仍然悬而未决。在此，我们报告了在弱聚焦光束的傅里叶平面中，在距正入射约0.12°处测量SHEL的模拟和实验结果，该光束在空气 - 玻璃界面反射。在反射光束的暗场区域实现了对由于光束横截面沿X和Y方向小于0.05°的偏振变化而导致的横向自旋位移的测量。我们在近正入射时无需移动光机械部件就能测量SHEL的能力以及对相偏振变化显著提高的灵敏度，有望在回射几何结构中实现多种应用，包括具有显著优势的材料表征。
