Most images taken with a camera lens are flat and two-dimensional. Increasingly, 3D imaging technologies provide the decisive depth for scientific and medical applications. 4-D imaging, which adds information about light polarization, can open up even more possibilities, but usually the equipment is bulky, expensive and complicated. Now, researchers who reported in ACS Nano have developed self-assembling liquid crystal microlenses that can reveal 4-D information in a snapshot.
Polarized light contains waves that are wave-shaped in a single plane, while unpolarized light, such as that from the sun, contains waves that move in all directions. Light can be polarized by reflecting away objects, and detecting this type of light can reveal hidden information. For example, cancer cells may reflect polarized light differently than healthy tissues. Wei Hu, Yan-Qing Lu and colleagues wanted to develop a portable, inexpensive and easy-to-use microlens to simultaneously obtain information on 3D space and polarization and thus produce 4-D images.
To make their microlenses researchers used liquid crystals, materials found in most electronic displays. With a self-assembly process, they patterned matrices of liquid crystal microlenses in concentric circles. The researchers used a polarized optical microscope to form objects, such as a cross or the letter "E", under different directions of linearly polarized light. Microlenses in the matrix depicted the object in different ways, depending on their distance from the object (depth) and the direction of polarized light, providing 4-D information. Although resolution must be improved, the technology can one day be used in applications such as medical imaging, communication, screens, information encryption and remote sensing, the researchers say.
Portable polarization sensitive camera can be used in machine vision, autonomous vehicles, safety and more
Ling-Ling Ma et al. Self-assembled asymmetric microlenses for four-dimensional visual imaging, ACS Nano (2019). DOI: 10.1021 / acsnano.9b07104
4-D Imaging with Liquid Crystal Micro Lenses (2019, November 20)
retrieved November 20, 2019
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