Surface plasmon polariton probes have important applications in super-resolution imaging and sensing. However, conventional probes often rely on complex radially polarized light excitation and struggle to achieve high-intensity electric field enhancement localized at the tip, which limits their practical performance. This paper proposes a double-slit plasmonic platform-based fiber probe that enables efficient nanofocusing under linearly polarized light by integrating the Fabry-Pérot interference enhancement mechanism of the platform-based structure with the polarization control function of the asymmetric half-ring slit. We introduce an innovative sleeve ring etching technique that increases the tip curvature by more than an order of magnitude while also addressing the issue of uncontrollable morphology in conventional probe fabrication. Experimental results demonstrate that the proposed probe exhibits an electric field strength at the tip that is six times higher than that of an asymmetric double-slit probe at a wavelength of 633 nm. Furthermore, it maintains stable focusing across a broadband range from 580 nm to 800 nm, with particularly significant enhancement in the short-wavelength region. Additionally, this probe achieves a resolution of 28.6 nm in optical imaging experiments, enabling simultaneous characterization of both morphological and optical properties of deep subwavelength-sized samples under ambient conditions.

Multi-view fringe projection profilometry systems that integrate a telecentric projector with multiple oblique-view cameras offer unique advantages for inspecting high dynamic-range surfaces featuring densely packed, intricate microstructures. Nevertheless, such systems encounter fundamental calibration challenges, namely, sign ambiguity in the rotation matrices and truncated extrinsic parameters inherent to telecentric projector models, as well as difficulties in multi-view point cloud registration. This paper introduces a novel calibration framework with three principal contributions. First, we resolve the sign ambiguity by calibrating the telecentric projector under a quasi pinhole model and directly transferring the extrinsic sign conventions, thereby obviating the need for costly precision displacement stages or elaborate virtual targets. Second, we fix the axial-gauge freedom by constraining the origin of the projector coordinate system to lie on the XY-plane of the camera coordinate system. Third, we establish precise relative poses between all cameras and a designated reference camera, enabling unified multi-view point cloud registration directly within the projector coordinate frame, which substantially reduces alignment errors and accelerates data processing. Experimental results demonstrate marked improvements in accuracy: reprojection root-mean-square errors of 0.084 pixels for the cameras and 0.106 pixels for the projector, corresponding to in-plane spatial resolutions of 0.21 µm and 0.26 µm, respectively. The proposed method offers a robust solution for micron-level inspection in semiconductor packaging and precision manufacturing.