Super-resolution imaging using super-oscillatory diffractive neural networks

TL;DR

This paper introduces SODNN, a super-oscillatory diffractive neural network that achieves super-resolution imaging beyond diffraction limits with improved performance, multi-wavelength capability, and extended depth of field.

Contribution

The paper presents a novel optical neural network design for super-resolution imaging that surpasses existing methods through advanced diffractive layers and nonlinear sensing.

Findings

Achieved a super-oscillatory spot with 0.407λ FWHM in the far field.

Demonstrated super-resolution imaging beyond diffraction limits.

Implemented multi-wavelength and multi-focus spot arrays to reduce chromatic aberrations.

Abstract

Optical super-oscillation enables far-field super-resolution imaging beyond diffraction limits. However, the existing super-oscillatory lens for the spatial super-resolution imaging system still confronts critical limitations in performance due to the lack of a more advanced design method and the limited design degree of freedom. Here, we propose an optical super-oscillatory diffractive neural network, i.e., SODNN, that can achieve super-resolved spatial resolution for imaging beyond the diffraction limit with superior performance over existing methods. SODNN is constructed by utilizing diffractive layers to implement optical interconnections and imaging samples or biological sensors to implement nonlinearity, which modulates the incident optical field to create optical super-oscillation effects in 3D space and generate the super-resolved focal spots. By optimizing diffractive layers with 3D optical field constraints under an incident wavelength size of $\lambda$, we achieved a super-oscillatory spot with a full width at half maximum of 0.407$\lambda$ in the far field distance over 400$\lambda$ without side-lobes over the field of view, having a long depth of field over 10$\lambda$. Furthermore, the SODNN implements a multi-wavelength and multi-focus spot array that effectively avoids chromatic aberrations. Our research work will inspire the development of intelligent optical instruments to facilitate the applications of imaging, sensing, perception, etc.