Applied Optics Group, School of Physics, National University of Ireland, Galway, University Road, Galway, Ireland.
Phys Rev Lett. 2010 Jun 25;104(25):253601. doi: 10.1103/PhysRevLett.104.253601. Epub 2010 Jun 22.
We show, both theoretically and experimentally, that high-numerical-aperture (NA) optical microscopy is accompanied by strong spin-orbit interaction of light, which translates fine information about the specimen to the polarization degrees of freedom of light. An 80 nm gold nanoparticle scattering the light in the focus of a high-NA objective generates angular momentum conversion, which is seen as a nonuniform polarization distribution at the exit pupil. We demonstrate remarkable sensitivity of the effect to the position of the nanoparticle: Its subwavelength displacement produces the giant spin-Hall effect, i.e., macroseparation of spins in the outgoing light. This brings forth a far-field optical nanoprobing technique based on the spin-orbit interaction of light.
我们从理论和实验两方面证明，高数值孔径（NA）光学显微镜伴随着强烈的光自旋轨道相互作用，这种相互作用将样品的细微信息转化为光的偏振自由度。在高数值孔径物镜的焦点处散射光的 80nm 金纳米粒子会产生角动量转换，这表现为出射光瞳处非均匀的偏振分布。我们证明了该效应对纳米粒子位置的显著敏感性：其亚波长位移产生了巨大的自旋霍尔效应，即出射光中自旋的宏观分离。这带来了一种基于光的自旋轨道相互作用的远场光学纳米探测技术。
