Wide field-of-view metalens: a tutorial

Abstract

.Wide field-of-view (FOV) optics are essential components in many optical systems, with applications spanning imaging, display, sensing, and beam steering. Conventional refractive wide FOV optics often involve multiple stacked lenses, resulting in large size and weight as well as high cost. Metasurface lenses or metalenses promise a viable solution to realizing wide FOV optics without complex lens assembly. We review the various architectures of wide FOV metalenses, elucidate their fundamental operating principles and design trade-offs, and quantitatively evaluate and contrast their imaging performances. Emerging applications enabled by wide FOV metasurface optics are also discussed.

Wide-Field-of-View, Large-Area Long-Wave Infrared Silicon Metalenses

“…Compared to other WFOV designs such as quadratic phase 29−35 and doublet metalenses, 36−41 the present architecture is simple and yet does not compromise the imaging quality or optical efficiency. 42 The rest of this article is organized as follows. We start with formulating the overarching analytical design approach.…”

“…The choice of float-zone Si therefore contributes to suppression of the oxygen impurity absorption band while still enabling full leverage of industry-standard Si fabrication processes. Compared to other WFOV designs such as quadratic phase − and doublet metalenses, − the present architecture is simple and yet does not compromise the imaging quality or optical efficiency …”

Stereo Imaging with a Hemispherical Field-of-View Metalens Camera

“…However, while advancements in image processing tools have led to faster and more accurate depth estimation in stereo imaging, effectively fulfilling the diverse requirements of various applications, it is important to note that the use of traditional refractive lenses imposes certain limitations on camera functionalities and size. To circumvent these issues, dielectric metasurfaces, i.e., arrays of nanostructures with subwavelength dimensions, patterned on a thin (typically glass) substrate, are promising alternatives to replace refractive optical systems with advantages in terms of the form factor, unprecedented functionalities, and cost-effectiveness, due to their large-scale manufacturability. − In this regard, metalenses, i.e., metasurfaces acting as lenses, ,− have shown particular promise due to their ability not only to replace but to outperform traditional lenses by, e.g., enabling advanced functionalities that are difficult, if not impossible, to achieve with a single refractive lens (such as near-unity NA focusing , and single layer wide FOV imaging − ). In the context of 3D detection, metalenses have been explored using different concepts such as the dispersive behavior of metalenses, bifocal metalenses, complex engineered point-spread functions, − or stereo imaging with binocular metalens for short-range underwater imaging .…”

Metalens with tilted structures for high-efficiency focusing at large-angle incidences

“…However, due to the limited FOV of each metalens, the realization of wide-angle imaging has been hindered. Recently remarkable efforts have been made to achieve wide FOV imaging [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] , such as topology-optimized multilayered metalenses [18] , quadratic metalenses [19] , metalens doublets [20,21] , and hybrid metalenses [22] , while these designs are complex and usually need to sacrifice in certain aspects of imaging performance (e.g., degraded focusing quality, decreased entrance pupil). Recently researchers [25] developed a metalens array to compose an array-based camera and obtained a 120°-wide viewing angle.…”