Binocular Meta-lens for Underwater Imaging and Sensing

Project: Research

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Underwater optics in all aquatic environments is vital for environmental management, biogeochemistry, phytoplankton ecology, benthic processes, global change, etc. Many optical techniques of observational systems for underwater imaging and depth sensing have been developed. Binocular stereo vision is the common way to see the target and detect depth, such as humans or some predators. Currently, the binocular stereo vision system is composed of two cameras, and complex data transformation to calibrate two camera systems is needed. Most importantly, the underwater application scenario may be cramped and inaccessible for the bulky and complicated configuration optical system. This is a challenge in various aquatic environments and led to the high demands for an integrated optical system with compactness and efficiency. Meta-devices are advanced flat optical devices composed of subwavelength nanostructures acting as nano-antennas. Optical meta-devices can manipulate the incident electromagnetic waves' phase, amplitude, polarization, etc. Meta-devises can achieve novel functions beyond the original and natural optical materials and traditional optical components. The advantages of the optical meta-device are lightweight, compact, durable, and versatile. Here, we propose a novel binocular meta-optic device for underwater depth sensing and imaging. Considering the tolerance to environmental conditions, including temperature, humidity, and pressure, we choose gallium nitride (GaN) as the base material for the meta-lens. GaN is a chemically and mechanically stable compound with very high resistance to the environment of extreme conditions. A GaN binocular meta-lens will be specifically designed and fabricated to demonstrate underwater stereo vision and depth sensing. The advantages of our binocular meta-lens are no spherical phase aberration and no need for distortion correction or camera calibration, which is necessary for traditional two-camera stereo vision systems. We expect the results of imaging and depth measurements can be optical diffraction limits. In the meantime, we will develop the generalized depth calculation formula for all-size binocular vision systems. We will also introduce deep learning for image processing to improve data processing efficiency and realize the fast depth and image computation in real time. Besides the aberration-free advantage of flat meta-optic components, the intrinsic super-hydrophobicity properties of our nanostructured GaN meta-lens will enable an anti-adhesion, stain-resistant, and self-cleaning novel underwater imaging device. We believe the significant impact of this project can promote the revolution of next-generation underwater optical devices and systems, such as all aquatic environments micro/nano-robots, mini-submarine machine vision, marine ecological surveys, etc.


Project number9043572
Grant typeGRF
Effective start/end date1/08/23 → …