Analog Computational Imaging with Meta-Optics : From image processing to structured illumination

Abstract

Conventional optical information processing systems, particularly those used for real-time image transformation and analysis, face growing limitations in terms of size, speed, energy efficiency, and integration with electronic systems. Traditional optical components lack the flexibility to perform complex processing tasks in a compact format, while digital image processing suffers from latency and power inefficiencies due to sequential and resource-intensive computations. These challenges drive the need for new approaches that enable compact, high-speed, and energy-efficient manipulation of light fields and analog image processing.

Meta-optics, which are planar optical elements composed of subwavelength-engineered meta-atoms, offer a transformative solution to these challenges. By providing precise control over the phase, amplitude, and polarization of light at the subwavelength scale, this thesis explores meta-optical approaches for advancing optical information processing and computational imaging, aiming to develop high-speed, energy-efficient, and miniaturized imaging and sensing systems.

The first part of this thesis introduces a meta-optical azimuthal shearing interferometer that enables real-time, broadband edge detection, differential interference contrast microscopy, and wavefront sensing. By embedding birefringent nanopore structures into silica substrates via laser direct writing, this compact device achieves robust, broadband azimuthal shear interference within a common-path configuration, eliminating the need for complex alignment or bulk optics.

Building on the broader potential of meta-optics, the thesis next introduces a platform of generalized meta-operators based on double-phase encoding and polarization multiplexing, capable of performing diverse analog optical computations. Operating at visible wavelengths, these metasurfaces implement tasks such as first- and second-order spatial differentiation and cross-correlation-based pattern recognition, enabling direct light-field manipulation without the need for digital post-processing. Additionally, the same platform is utilized to achieve high-fidelity three-dimensional meta-holography, demonstrating volumetric wavefront reconstruction with a single-layer optical element.

Finally, this thesis advances the capabilities of meta-optics in structured illumination by introducing a polarization-encoded metasurface platform for generating high-fidelity phase-shifting fringe patterns. This static, polarization-controlled approach enables the generation of phase-shifting sinusoidal fringe patterns without requiring active modulation or tunable elements, enabling compact fringe projection profilometry for three-dimensional surface measurement and super-resolution structured illumination microscopy.

This thesis establishes meta-optics as a versatile platform for embedding analog optical processing into modern imaging systems, enabling compact, high-speed, and energy-efficient solutions. By combining meta-optical analog computing with computational imaging techniques, the methods developed here advance the functionality of optical systems beyond the limitations of conventional electronic processing. These results lay the groundwork for next-generation intelligent photonic devices, with broad potential applications in biomedical imaging, machine vision, precision metrology, optical sensing, and advanced optical information processing.