Abstract
Abstract Optical imaging systems, like microscopes, cameras, and telescopes, continue to expand the scope of human observation of the world. As one of the key indicators of imaging systems, the field-of-view (FOV) is often limited by coma aberration. Expanding it generally relies on a combination of complex lenses, leading to a bulky and cumbersome system. Recently, the emergency of meta-optics provides an alternative to constructing compact and lightweight large-FOV metalens through elaborated phase modulation within a flat surface, showing great potential in surveillance, unmanned vehicles, onboard planes or satellites, medical science, and other new applications. In this article, we review recent advances of wide-angle metalenses, including operation principles, design strategies, and application demos. Firstly, basic principles of wide-angle imaging using a single metalens are interpreted. Secondly, some advanced methods for designing subwavelength structures with high angle robustness and high efficiency are discussed. Thirdly, some representative functional devices and applications are surveyed. Finally, we conclude with an outlook on future potentials and challenges that need to be overcome.
Highlights
As an effective expansion of the human eye, optical imaging systems like microscopes and telescopes open the door to the micro world and the macro world, wherein classical laws of refraction and reflection have underpinned the development of optical systems for hundreds of years
The current advances in micro-nano fabrication technology have allowed significant integration of many optical elements, such as ultracompact multi-lens objectives [1], high numerical aperture (NA) microlens arrays [2, 3], and other micro-optical elements [4,5,6], these devices still rely on classical laws of refraction and reflection and the pixel size of these devices is generally about tens of light wavelengths, leading to limited optical performances
Metasurfaces consisting of subwavelength structures have shown great potential to trigger an optical revolution of Engineering Optics from 1.0 to 2.0 [7], which benefits from its unprecedented electromagnetic properties not available in natural materials
Summary
As an effective expansion of the human eye, optical imaging systems like microscopes and telescopes open the door to the micro world and the macro world, wherein classical laws of refraction and reflection have underpinned the development of optical systems for hundreds of years. One metalens can readily enable a high-NA hyperbolic phase profile to be free from spherical aberration, resulting in high diffraction-limited resolution [69] This property is difficult to obtain in traditional optics, especially with a single element, owing to the difficulty in mask an aspherical lens with large curvature [74]. Ultra-large FOV (178°) diffraction-limited imaging has been experimentally demonstrated using a single wide-angle metalens with unprecedented imaging performance regarding the efficiency and angular range [82]. This review concentrates on recent advances of large-FOV imaging technology based on single-chip wide-angle metalenses.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
