High Contrast Ultrathin Light‐Field Camera Using Inverted Microlens Arrays with Metal–Insulator–Metal Optical Absorber

• Published in: Advanced optical materials Vol. 9; no. 6
• Main Authors: Bae, Sang‐In, Kim, Kisoo, Jang, Kyung‐Won, Kim, Hyun‐Kyung, Jeong, Ki‐Hun
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-03-2021
• Subjects: Absorbers; Arrays; Biomedical materials; Biometrics; Cameras; Crosstalk; depth estimation; Electromagnetic absorption; Field cameras; high resolution; Image acquisition; Image contrast; Inspection; Light; light‐field camera; Materials science; metal–insulator–metal absorber; microlens arrays; Microlenses; Microscopes; Optics
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202001657

Light‐field imaging has attracted much attention in constructing 3D objects with a simple configuration and capturing all the spatial and directional data in a single photographic exposure. Here, an ultrathin light‐field camera (ULFC) for high contrast and high‐resolution light‐field imaging using a metal–insulator–metal optical absorber based inverted microlens arrays (MIM‐iMLA) is reported. A metal–insulator–metal based optical absorber (MIM‐OA) between microlenses exhibits high light absorption in the full visible region, thereby highly blocking microlens crosstalk. The MIM‐iMLA double the image contrast and improve MTF50 by up to 32%, compared to conventional light‐field image. In addition, the MIM‐iMLA substantially reduces an image plane distance and brings the objective lens position closer to the MLA. The ULFC exhibits a short total track length of 5.1 mm, demonstrating high contrast light‐field image acquisition and high accuracy 3D depth map estimation after light‐field rendering. This ultrathin and high contrast light‐field camera can provide a new platform for miniaturized 3D cameras in biomedical applications, biometrics, automated inspection, or mobile camera applications.
This article reports an ultrathin light‐field camera (ULFC) using a metal–insulator–metal optical absorber based inverted microlens arrays (MIM‐iMLA) for high contrast and high‐resolution light‐field image acquisition. MIM‐iMLA double the image contrast, and the rendered ULFC image shows an MTF50 value improvement of 32%. The ULFC has successfully demonstrated high contrast light‐field image acquisition as well as high accuracy 3D depth map estimation.