A groundbreaking innovation enables the transformation of any smartphone or TV display into a holographic projector, thanks to a new method developed by scientists. Specifically, they’ve devised a technique that harnesses “incoherent light” emitted by mobile devices, such as the iPhone 14 Pro, to generate holographic projections.
Utilizing a device called a spatial light modulator (SLM), researchers successfully converted a 2D image displayed on an iPhone 14 Pro into a vivid 3D hologram. Their findings, outlined in a study published on April 2 in the journal Optics Letters, detail the process of creating multi-layered holograms through what they term a “cascade of holograms.”
This cascade begins with a static color image displayed on the iPhone screen. Light waves emitted from the image are then meticulously refined using the SLM, a device capable of controlling the phase, amplitude, and polarization of light waves. Through iterative adjustments facilitated by the SLM, the researchers built up the 3D holographic image layer by layer.
To achieve this holographic effect, the scientists employed a reverse-engineering approach, determining the precise adjustments required to manipulate the light waves at each step of the process. By capturing images at critical points using a color image sensor positioned at the focal point of a Fourier transform lens (FTL), they demonstrated the holographic display’s ability to project images in three dimensions.
What sets this research apart is its utilization of “incoherent” light from everyday devices like smartphones and laptops to create holographic displays. Traditionally, holography relies on “coherent” light sources like lasers, which offer greater control but come with practical limitations and potential safety concerns.
The absence of lasers in this method eliminates issues like speckle noise, enhancing visual quality and clarity. Despite the inherent challenges posed by incoherent light, the researchers successfully structured chaotic light waves from the iPhone into precise 3D images through the cascade of holograms.
This breakthrough not only offers a more accessible and cost-effective approach to holographic displays but also holds promise for applications in augmented and virtual reality devices, including compact and safe near-eye displays like smart glasses.