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The optical set-up consists of a deformable mirror and the scattering medium with two successive holographic diffusers. A high-numerical-aperture imaging unit mounted on a three-axis motorized translational system is utilized for wavefront optimization and imaging. (Credit: Korea Advanced Institute of Science and Technology)

With the addition of holographic diffusers or frosted glasses to wavefront modulators, researchers offer a simple and practical solution to significantly enhance the performance of 3D dynamic holographic displays by 2,600 times. One potential application of 3D digital holograms is biomedical imaging. This study is expected to improve the limited size and viewing angle of 3D images, which were a major problem of the current holographic displays.

The researchers used a deformable mirror and added two successive holographic diffusers to scatter light. By scattering light in many directions, this allows for a wider viewing angle and larger image, but results in volume speckle fields, which are caused by the interference of multiple scattered light. Random volume speckle fields cannot be used to display 3D images.

To fix the problem, the researchers employed a wavefront-shaping technique to control the fields. They succeeded in producing an enhanced 3D holographic image with a viewing angle of 35 degrees in a volume of 2 cm in length, width, and height. This yielded a performance that was about 2,600 times stronger than the original image definition generated when they used a DM without a diffuser. The study was published online in Nature Photonics.

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