Broadband and large-aperture metasurface edge encoders for incoherent infrared radiation

Abstract

The prevalence of computer vision systems necessitates hardware-based approaches to relieve the high computational demand of deep neural networks in resource-limited applications. One solution would be to off-load low-level image feature extraction, such as edge detection, from the digital network to the analog imaging system. To that end, this work demonstrates incoherent, broadband, low-noise optical edge detection of real-world scenes by combining the wavefront shaping of a 24-mm aperture metasurface with a refractive lens. An inverse design approach is used to optimize the metasurface for Laplacian-based edge detection across the 7.5- to 13.5-μm LWIR imaging band, allowing for facile integration with uncooled microbolometer-based LWIR imagers to encode edge information. A polarization multiplexed approach leveraging a birefringent metasurface is also demonstrated as a single-aperture implementation. This work could be applied to improve computer vision capabilities of resource-constrained systems by leveraging optical preprocessing to alleviate the computational requirements for high-accuracy image segmentation and classification.

Achromatic and Coma-Corrected Hybrid Meta-Optics for High-Performance Thermal Imaging

“…Metasurfaces, made up of two-dimensional subwavelength artificial structure arrays, have been exhibited to provide a flat, efficient, and compact platform for manipulating different characteristics of light. 6−8 Various planar meta-optics based on metasurfaces are demonstrated to achieve equivalent functionalities as bulky optical components, such as holography, 9 structured light generators, 10 and optical focusing and imaging, 11,12 and even realize special or multiple optical functionalities that bulky optical components are unable to access, such as generation of complex structured light, 13 optical (or optoelectronic) analogue computing, 14,15 and tunable or multifunctional flat optics. 16,17 Metalenses, one of the most representative metasurface devices, are used for focusing light and imaging applications.…”

“…Metasurfaces, made up of two-dimensional subwavelength artificial structure arrays, have been exhibited to provide a flat, efficient, and compact platform for manipulating different characteristics of light. − Various planar meta-optics based on metasurfaces are demonstrated to achieve equivalent functionalities as bulky optical components, such as holography, structured light generators, and optical focusing and imaging, , and even realize special or multiple optical functionalities that bulky optical components are unable to access, such as generation of complex structured light, optical (or optoelectronic) analogue computing, , and tunable or multifunctional flat optics. , Metalenses, one of the most representative metasurface devices, are used for focusing light and imaging applications. − Metalenses are of high spatial resolution and wavelength-scale functional layer thickness and are able to be fabricated via the method compatible with standard semiconductor processing, which is very promising for miniaturized, lightweight, and low-cost optical imaging systems. Until now, various metalenses have been experimentally achieved via low-absorption dielectric metasurfaces in different electromagnetic bands such as extreme ultraviolet, visible, − and infrared − bands.…”