Using optical waveguide materials, this technology can achieve holographic imaging without the need for beam splitters and prisms

Recently, a group of researchers from Duke University in the United States published a paper on new color holographic technology. It is reported that this technology can be used in AR glasses, smartphones, and head-up displays, and can complete 3D color imaging without heavy optical components.

According to Qingting.com, researchers at Duke University stated in a paper that they were able to encode color images into a 300x300 micron pixel in a two-dimensional optical waveguide structure (very thin, used to guide light). Hologram. When the grating coupler is illuminated with red, green and blue light, the computer-generated hologram creates a complex color holographic image.

Daniel L. Marks, one of the researchers in the group, said: “Holographic photos can be printed directly on the lenses of AR glasses, so that no heavy optical components, beam splitters or prisms are needed to directly print them. The image is projected into a person's pupil. This technology can also be used to project 3D images from smartphones onto walls. ”

This new manufacturing process requires encoding holograms into compatible integrated photons. Among technological materials, that is to say, if the same manufacturing process as computer chips is used, this kind of holographic device can be easily mass-produced. Holographic photo-generating components produced using the above technology can be placed in devices that support chips and have light sources that can generate 3D images.

Solve the problem of single color

The color holographic imaging technology mentioned in the paper is based on computer-generated holographic photos. Unlike traditional holographic imaging, it does not require actual objects and lasers, and uses digital This method can generate interference patterns and generate holographic images.

Computer-generated holograms can produce high-resolution 3D images, but to solve the problem of single colors, researchers at Duke University created a grating, a series of stripes, and a binary hologram ( Built into an optical waveguide made of photoresist, a light-sensitive material). They developed a method that integrates red, green and blue interference patterns into a binary holographic pattern.

Huang Zhiqin, the first author of the paper, said: "One of the challenges we encountered was how to mix colors to generate color images, and then separate them accurately to generate full-color images. Our method allows The entire process is implemented in one plane. ”

Another challenge they encountered was how to create a holographic imaging device in an optical waveguide structure, because traditional methods (making color computer-generated holograms) did not work. Use optical waveguides.

The effect is good enough

After testing, the holographic imaging method developed by this group of researchers can encode color holographic photos of apples, flowers, and birds. The holographic images generated are far from theoretical predictions. Not big. Although in the demo, they only used 300x300 micron holograms, they said that it is not difficult to scale up, and the technology can also be combined with existing technologies (such as LCD screen production processes) to generate dynamic images.

Next, this group of researchers will continue to optimize this technology and reduce the light loss caused by the holographic photo encoding structure. They also pointed out that combining this structure with an integrated laser-based device would lead to more practical application scenarios.

This article is translated by Qingting.com from: Duke