What if you could film a three-dimensional movie not with a high-end camera or bulky equipment but with just a single pixel? That’s not a scene from a sci-fi flick but a real scientific breakthrough from Kobe University, Japan. Researchers there have unveiled a cutting-edge method that brings holographic video microscopy into sharper, faster, and more flexible focus.
Holograms aren’t just flashy gimmicks on your credit cards or banknotes—they’re rapidly becoming essential tools in scientific exploration. In the realm of holographic video microscopy, these light-based marvels allow researchers to view and analyze microscopic particles in three dimensions and in real time. This involves capturing a series of video frames and analyzing how light scatters off the sample, pixel by pixel.
Traditionally, recording such holograms requires the precision of laser-based setups. Two prominent techniques in this field are FINCH (Fresnel Incoherent Correlation Holography) and OSH (One-Pixel Holography). FINCH is known for its speed and compatibility with visible light, but it demands a clear line of sight to the sample. OSH, on the other hand, can peer through scattering materials and use non-visible light—imagine being able to see through biological tissues—but it’s frustratingly slow for capturing motion.
This is where Dr. Yoneda Naru and his team stepped in with a bold question: why not combine the best aspects of both systems? Their hybrid approach aims to retain OSH’s ability to image through obstructions while dramatically improving its speed.
The key? A digital micromirror device (DMD) capable of operating at a staggering 22 kilohertz. Dr. Yoneda described the leap in speed with a vivid analogy:
“This device operates at 22 kHz, whereas previously used devices have a refresh rate of 60 Hz. This is a speed difference that’s equivalent to the difference between an old person taking a relaxed stroll and a Japanese bullet train.”
Their experimental results confirmed the system’s ability to record moving 3D images and even film through light-scattering materials like a mouse skull. Although the current frame rate hovers at just over one frame per second, the team is optimistic. By employing a technique known as sparse sampling, which strategically skips redundant image data, they believe they can reach a standard video frame rate of 30 Hz.
This holds remarkable promise for medical and biological imaging. Imagine observing living tissues and tracking active processes in three dimensions—without needing to cut, probe, or disrupt the body.
“We expect this to be applied to minimally invasive, three-dimensional biological observation, because it can visualize objects moving behind a scattering medium,” a researcher noted.
Of course, the journey isn’t over. Challenges remain, including the need to boost resolution and sampling rates. According to Dr. Yoneda:
“For that, we are now trying to optimize the patterns we project onto the samples and to use deep-learning algorithms for transforming the raw data into an image.”
Meanwhile, the global race to elevate holographic technology is heating up. In Spain, researchers at UPNA have crafted floating 3D graphics that can be manipulated by hand, straight out of science fiction. And in South Korea, efforts are underway to convert ordinary 2D video into fully dynamic, floating 3D holograms.
