Virtual reality (VR) headsets have the ability to transform the way we interact with digital content by immersing users in three-dimensional environments. This is generally accomplished by positioning traditional displays in front of the eyes to simulate three-dimensional experiences. By combining these displays with sensors and other supporting hardware, such as gyroscopes and accelerometers, the headsets track head movements and adjust the visual scene accordingly. However, packing all of this hardware into a headset makes it bulky and expensive, making them uncomfortable for long-term use and limiting their widespread adoption.
Holography presents a promising alternative display technology for both VR and augmented reality (AR). Unlike traditional displays, holographic images offer real depth because they are genuinely three-dimensional, providing a more natural and immersive experience. This approach holds great potential for creating lighter and more comfortable headsets, as the technology required for holography can be compact enough to fit on a pair of standard glasses. The key component enabling holography is the spatial light modulator, a chip-like device that manipulates light to create images with depth.
The expander works with existing technologies (📷: E. Tseng et al.)
However, spatial light modulator technology is limited in that it can only create images that are either small and clear or large and fuzzy. This makes it impossible to deliver the high-quality, expansive visuals that are needed for VR and AR applications. Recent work done by researchers at Princeton University and Meta may soon shatter these present limitations, however. They have developed a novel device that works in conjunction with a spatial light modulator to expand its field of view, making large, clear holographic images possible.
The team’s device is a very small piece of frosted glass that could easily be incorporated into a standard, lightweight pair of glasses. This simplicity hides the advanced optical techniques and artificial intelligence algorithms (AI) that went into its production. Of course not just any piece of frosted glass would have the desired effect. This particular device has a very unique pattern etched into its surface, the development of which was guided by optics and AI.
An example of an expanded holographic image (📷: Princeton University)
The surface of the glass scatters light from the spatial light modulator in just such a way that certain elements of images are moved into different frequency bands — some of which are only barely perceptible to the human eye. This has the effect of increasing the size of the holographic image, and therefore the field of view of a user of the system. Crucially, this expansion in size does not make the image fuzzy.
While the image is far clearer than is possible with existing technologies, there is some drop in quality. We are accustomed to ultra-high-resolution displays in our VR and AR systems, so further work will be needed to make this novel display fully acceptable to users. But with some additional refinements, this could be a key factor in making VR and AR more practical and finally achieving the dream of making it accessible to everyone.