Nanometer Interlaced\nDisplacement Metrology Using\nDiffractive Pancharatnam-Berry and Detour Phase Metasurfaces

Resolving structural misalignments on the nanoscale is\nof utmost\nimportance in areas such as semiconductor device manufacturing. Metaphotonics\nprovides a powerful toolbox to efficiently transduce information on\nthe nanoscale into measurable far-field observables. In this work,\nwe propose and demonstrate a novel interlaced displacement sensing\nplatform based on diffractive anisotropic metasurfaces combined with\npolarimetric Fourier microscopy capable of resolving a few nanometer\ndisplacements within a device layer. We show that the sensing mechanism\nrelies on an interplay of Pancharatnam-Berry and detour phase shifts\nand argue how nanoscale displacements are transduced into specific\npolarization signatures in the diffraction orders. We discuss efficient\nmeasurement protocols suitable for high-speed metrology applications\nand lay out optimization strategies for maximal sensing responsivity.\nFinally, we show that the proposed platform is capable of resolving\narbitrary two-dimensional displacements on a device.