Full-color 3D display method shows potential to enhance augmented and virtual reality experiences. Scientists have created a method to create 3D full-color holographic images using smartphone screens instead of lasers. This innovative technique, with further improvements, has the potential for augmented or virtual reality displays.
Whether augmented and virtual reality displays are used for gaming, education, or other applications, incorporating 3D displays can create a more realistic and interactive user experience.
"Although holography methods can create very realistic 3D images of objects, traditional approaches are impractical because they rely on laser sources", — said the leader of the research group 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 Optica Publishing Group Optics Letters researchers describe their new method, which is based on computerized holography (CGH). Thanks to a new algorithm they developed, they were able to use only an iPhone and an optical component called a spatial light modulator to reproduce a color 3D image that consisted of two holographic layers.
«We believe this method could ultimately be useful for minimizing optics, reducing costs and potential eye damage in future visual interfaces and 3D displays»,— 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 hands-on approach
Although CGH uses algorithms to generate images, coherent light from a laser is usually required to display these holographic images. In a previous study, the researchers showed that spatiotemporal incoherent light emitted by a white embedded LED can be used for CGH. However, this installation required two spatial light modulators — devices that control the wavefronts of light — which is impractical due to their cost.
In a new study, researchers have developed a less expensive and more practical incoherent CGH method. "This work is consistent with our lab's focus on computational imaging, a research field dedicated to innovative optical imaging systems by integrating optics with informatics,— Horisaki said. "We focus on minimizing optical components and eliminating impractical requirements in conventional optical systems".
The new approach passes light from the screen through a spatial light modulator that presents multiple layers of a full-color 3D image. While this may sound simple, it required careful modeling of the process of incoherent light propagation from the screen, and then using that information to develop a new algorithm that coordinated the light coming from the device's screen using a single spatial light modulator.
Holographic images from a smartphone
"Holographic displays that use low-coherence light can provide lifelike 3D displays, potentially reducing cost and complexity,— said Shigematsu. "While several groups, including ours, have demonstrated holographic displays using low-coherence light, we took this concept to the extreme using a smartphone display.
To demonstrate the new method, the researchers created a two-layer optical reproduction of a full-color 3D image , displaying one holographic layer on the iPhone 14 Pro screen, and the second — on the spatial light modulator. The resulting image measures a few millimeters on each side.
Researchers are now working to improve the technology so that it can 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.