The Institute of Photonic Technology.
A group of researchers from Korea, Australia, Great Britain, and Germany were able for the first time to modify an optical glass fiber in such a way that light of different wavelength can be focused very precisely. 3D printing an optical lens at the end of the fiber can achieve a level of accuracy.
There are new possibilities for applications in endoscopy and laser therapy. Their results were published in a journal.
The end faces of optical fibers have a disadvantage. A shift in the focal point of the image is caused by the fact that the light of different wavelength is shaped differently. A remedy is provided by achromatic glasses.
A meta lens is used to focus light.
An achromatic lens, which is attached to the end of an optical fiber, has been realized for the first time by an international team
The ultrathin polymer-based lens consists of a complex design of geometric structures. The hollow tower structure was printed on the tip of a commercial optical fiber. In this way, light can be focused on a focal point and images with high resolution can be created.
The researchers realized a meta lens with a diameter of 100 micrometers and a NA of 0.2, which is significantly higher than the achromatic lens on the end of fiber end faces. It is possible to focus light in the range of 400 nanometers with the help of the lens.
There are different heights for the individualnanopillars, ranging from 8.5 to 13 micrometers. The different wavelength of light can be focused on one focal point.
They achieved convincing image quality with high image acquisition efficiency and highchromatic image contrast by using a fiber with a meta-optics in an experiment. Even at different wavelength, the focus positions were almost always the same.
Light shape for a wide range of applications.
Since the meta lens is extremely small and flat, a fiberoptic design with achromatic optics at the top can be used to further advance the miniaturization and flexibility of endoscopy.
Further areas of application in the field of laser-assisted therapy and surgery are seen by the researchers.
More information: Haoran Ren et al, An achromatic metafiber for focusing and imaging across the entire telecommunication range, Nature Communications (2022). DOI: 10.1038/s41467-022-31902-3 Journal information: Nature Communications Provided by Leibniz Institute of Photonic Technology
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