3D Imaging Using Extreme Dispersion in Optical Metasurfaces

Abstract

Metasurfaces have the potential to revolutionize imaging technologies due to their extreme control of phase, polarization, and amplitude of the incident light. They rely upon enhanced local interaction of light to achieve the desired phase profile. As a consequence of the enhanced local interaction of light, metasurfaces are highly dispersive. This strong dispersion has been recognized as a primary limitation as it relates to realizing conventional imaging with metasurfaces. Here, we argue that this strong dispersion is an added degree of design freedom for computational imaging, potentially opening up novel applications. In particular, we exploit this strongly dispersive property of metasurfaces to propose a compact, single-shot, and passive 3D imaging camera. Our device consists of a metalens engineered to focus different wavelengths at different depths and two deep networks to recover depth and RGB texture information from chromatic, defocused images acquired by the system. In contrast with other metasurface-based 3D sensors, our design can operate in the full visible range with a larger field-of-view (FOV) and can potentially generate dense depth maps of complicated 3D scenes. Our simulation results on a 1 mm diameter metalens demonstrate its ability to capture 3D depth and texture information ranging from 0.12 to 0.6 m.

Single-shot 3D imaging with point cloud projection based on metadevice

“…These results verify that the proposed method enables the 3D reconstruction of object vibration and deformation. Meanwhile, the 3D reconstruction ability for low-texture objects renders the technique advantageous for active imaging techniques over passive imaging technique 39 , such as binocular stereo vision and depth from defocus. Note that our method can also work for measured scene with larger object size (Supplementary Note 10 ).…”

Spectrally Gated Microscopy (SGM) with Meta Optics for Parallel Three-Dimensional Imaging

“…The SGM mechanism when combined with the superior performances of flat optical components allows information from a large axial range to be simultaneously recorded; thus, the number of dimensions to be scanned is reduced to merely the lateral one. Several works have demonstrated depth information extraction with flat optics through chromatic dispersion , or by other means, , yet they lack the ability of sectioning out-of-focus light. Here we attained an axial sectioning resolution up to ∼800 nm, which can be further improved by introducing a higher finesse FP or reducing the focal length of the objective lens, a feature that is enabled by the introduction of flat components.…”

Ultrasensitive Molecular Detection at Subpicomolar Concentrations by the Diffraction Pattern Imaging with Plasmonic Metasurfaces and Convex Holographic Gratings

“…Due to the unique capabilities of manipulating light scattering in the subwavelength regime, metasurfaces with metallic and dielectric nanophotonic structures have emerged as promising techniques in many nanophotonic applications [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ] The subwavelength light scattering of metasurfaces is highly localized in the vicinity of the nanostructure and is highly sensitive to the geometry of the structure and local environment, which makes them excellent for the refractometric sensing of thin‐layer substances attached to the nanostructures of metasurfaces. [ 8 , 9 , 10 , 11 , 12 , 13 ] Benefiting from the highly concentrated electric field on the subwavelength nanophotonic structures of metasurfaces, numerous dielectric and plasmonic metasurface‐based sensors have been intensively investigated for the detection of gaseous chemicals, [ 14 ] biomolecules, [ 12 , 15 , 16 ] environmental pollutants, [ 17 , 18 ] and corrosion.…”

“…Due to the unique capabilities of manipulating light scattering in the subwavelength regime, metasurfaces with metallic and dielectric nanophotonic structures have emerged as promising techniques in many nanophotonic applications [1][2][3][4][5][6][7] DOI: 10.1002/advs. 202201682 The subwavelength light scattering of metasurfaces is highly localized in the vicinity of the nanostructure and is highly sensitive to the geometry of the structure and local environment, which makes them excellent for the refractometric sensing of thin-layer substances attached to the nanostructures of metasurfaces.…”