Metasurfaces have been studied and widely applied to optical systems. A metasurface-based flat lens (metalens) holds promise in wave-front engineering for multiple applications. The metalens has become a breakthrough technology for miniaturized optical system development, due to its outstanding characteristics, such as ultrathinness and cost-effectiveness. Compared to conventional macro- or meso-scale optics manufacturing methods, the micro-machining process for metalenses is relatively straightforward and more suitable for mass production. Due to their remarkable abilities and superior optical performance, metalenses in refractive or diffractive mode could potentially replace traditional optics. In this review, we give a brief overview of the most recent studies on metalenses and their applications with a specific focus on miniaturized optical imaging and sensing systems. We discuss approaches for overcoming technical challenges in the bio-optics field, including a large field of view (FOV), chromatic aberration, and high-resolution imaging.
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Design and analysis of extended depth of focus metalenses for achromatic computational imaging
Metasurface optics have demonstrated vast potential for implementing traditional optical components in an ultracompact and lightweight form factor. Metasurfaces, however, suffer from severe chromatic aberrations, posing serious limitations on their practical use. Existing approaches for circumventing this involving dispersion engineering are limited to small apertures and often entail multiple scatterers per unit cell with small feature sizes. Here, we present an alternative technique to mitigate chromatic aberration and demonstrate high-quality, full-color imaging using extended depth of focus (EDOF) metalenses and computational reconstruction. Previous EDOF metalenses have relied on cubic phase masks, where the image quality suffers from asymmetric artefacts. Here we demonstrate the use of rotationally symmetric masks, including logarithmic-aspherical, and shifted axicon masks, to mitigate this problem. Our work will inspire further development in achromatic metalenses beyond dispersion engineering and hybrid optical–digital metasurface systems.
more » « less- NSF-PAR ID:
- 10194507
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Photonics Research
- Volume:
- 8
- Issue:
- 10
- ISSN:
- 2327-9125
- Page Range / eLocation ID:
- Article No. 1613
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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