Full-color 3D imaging demonstrates the potential to enhance augmented and virtual reality experiences. Scientists have developed a method to create 3D, full-color holographic images using smartphone screens instead of lasers. This innovative technique has potential for augmented or virtual reality displays with further improvements.

Although augmented and virtual reality displays are used for gaming, education or other applications, the inclusion of 3D displays can create a more realistic and interactive user experience.

“Although holography techniques can create very realistic 3D images of objects, traditional approaches are impractical because they rely on laser sources,” said research team leader Ryoichi Horisaki from the University of Tokyo in Japan. “Lasers emit coherent light that is easy to control, but they make the system complex, expensive and potentially harmful to the eyes.”

In the magazine of Optica Publishing Group publishing group Optical Letters researchers describe their new method based on computerized holography (CGH). Thanks to a new algorithm they developed, they were able to use just an iPhone and an optical component called a spatial light modulator to reproduce a colorful 3D image consisting of two holographic layers.

“We believe this method could ultimately be useful for minimizing optics in future visual interfaces and 3D displays, reducing costs and potential eye damage,” said Otoya Shigematsu, first author of the paper. “More specifically, it has the potential to improve the performance of near-eye displays, such as those used in high-end virtual reality headsets.”

A more practical approach

Although CGH uses algorithms to create images, coherent light from a laser is often needed to display these holographic images. In a previous study, researchers showed that spatiotemporally incoherent light emitted by a white embedded LED could be used for CGH. However, this setup required two spatial light modulators (devices that control the wavefronts of light), which was impractical due to their cost.

In a new study, researchers have developed a cheaper and more practical non-inferior CGH method. “This work is consistent with our laboratory’s focus on computational imaging, an area of ​​research dedicated to innovative optical imaging systems by integrating optics with computing,” Horisaki said. said. “We focus on minimizing optical components and eliminating impractical requirements in traditional optical systems.”

The new approach passes light through the screen through a spatial light modulator, presenting multiple layers of a full-color 3D image. While this sounds simple, it required careful modeling of the process of incoherent light emission from the screen and then using this information to develop a new algorithm that coordinates the light from the device’s screen using a single spatial light modulator.

Holographic images from smartphone

“Using low-coherence light, holographic displays can provide realistic 3D images and potentially reduce cost and complexity,” Shigematsu said. said. “While various groups, including ours, have demonstrated holographic displays using low-coherence light, we have taken this concept to the extreme using a smartphone display.”

To demonstrate the new method, the researchers created a two-layer optical copy of a full-color 3D image by displaying one holographic layer on the iPhone 14 Pro screen and the other on a spatial light modulator. The resulting image is a few millimeters in size on each side.

Researchers are now trying to improve the technology to display larger 3D images with more layers. Additional layers will make the image more realistic, improving spatial resolution and allowing objects to appear at different depths or distances from the viewer.