arXiv subjects

Jesse Pietila

Publications and source records attributed to Jesse Pietila.

4 recordsLinked to original sources

arXiv2026

Meta-optical processors for broadband complex-field image operations

All-optical image processing provides a fast and energy-efficient alternative to conventional electronic systems by directly manipulating optical wavefronts. However, metasurface-based optical processors reported to date are often limited in functionality, operating bandwidth, or input modality, which restricts their adaptability across different image processing tasks. Here, we demonstrate a broadband metasurface platform capable of performing diverse analog image processing operations on both amplitude- and phase-encoded inputs. This platform is realized using a single-layer dielectric metasurface designed through an end-to-end, task-driven inverse design framework. By tailoring the spatial-frequency components of incident image wavefronts, the metasurface implements analog operations such as edge detection and pattern recognition across a 200nm wavelength bandwidth in the visible spectrum. Furthermore, we develop a compact processor architecture that integrates imaging and computation within a reduced optical footprint. These results establish a flexible and compact metasurface-based optical processor with strong potential for integration into practical imaging and optical computing systems.

physics.optics↗

arXiv2025

Phase-shifting structured illumination with polarization-encoded metasurface

Phase-shifting structured illumination is a powerful technique used across diverse imaging modalities, including 3D surface measurement, quantitative phase imaging, and super-resolution microscopy. However, conventional implementations often rely on mechanically driven or optoelectronically complex systems, limiting their compactness, stability, and integration. Here, we present a polarization-controlled dielectric metasurface that generates phase-shifting fringe patterns in the visible spectrum, enabling compact and robust structured light projection. The metasurface encodes distinct phase gratings for orthogonal polarizations, producing fringe patterns with relative lateral displacements that vary according to the polarization of the transmitted light. We experimentally demonstrate high-quality fringe generation and apply the structured illumination in a fringe projection profilometry system for 3D surface measurement of different objects. The metasurface integrates multiple phase-shifting steps into a single static device, offering a millimeter-scale footprint and compatibility with polarization multiplexing. This approach introduces a compact, passive solution for structured light generation with broad potential in next-generation optical metrology and advanced computational imaging.

physics.optics↗

arXiv2025

Meta-operators for all-optical image processing

All-optical image processing offers a high-speed, energy-efficient alternative to conventional electronic systems by leveraging the wave nature of light for parallel computation. However, traditional optical processors rely on bulky components, limiting scalability and integration. Here, we demonstrate a compact metasurface-based platform for analog optical computing. By employing double-phase encoding and polarization multiplexing, our approach enables arbitrary image transformations within a single passive nanophotonic device, eliminating the need for complex optical setups or digital post-processing. We experimentally showcase key computational operations, including first-order differentiation, cross-correlation, vertex detection, and Laplacian differentiation. Additionally, we extend this framework to high-resolution 3D holography, achieving subwavelength-scale volumetric wavefront control for depth-resolved reconstructions with high fidelity. Our results establish a scalable and versatile approach to computational optics, with applications including real-time image processing, energy-efficient computing, biomedical imaging, high-fidelity holographic displays, and optical data storage, driving the advancement of intelligent optical processors.

physics.optics↗

arXiv2022

Epsilon-near-zero nanoparticles

In this work, we propose epsilon-near-zero (ENZ) nanoparticles formed of metal and dielectric bilayers and employ the effective medium approach for multilayered nanospheres to study their optical response. We obtained a passive tunable ENZ region by varying the radii of the proposed bilayer nanospheres, ranging from visible to near-IR. In addition, we present the absorption and scattering cross-section of ENZ nanoparticles using an open-source, transfer-matrix-based software (STRATIFY). %, and a commercial FDTD software (LUMERICAL). The proposed ENZ nanoparticle is envisioned to be experimentally realized using chemical synthesis techniques.

physics.optics↗