Metamaterials for Holograms
Combined with Liquid Crystals Responsive to Electricity, Temperature, and Touch
The artificial intelligence named Jarvis appearing in the movie Iron Man
[Asia Economy Reporter Junho Hwang] A technology that accelerates the commercialization of holograms featured in the movie Iron Man has been developed in Korea. While existing holograms were limited to displaying a single image, a hologram device that changes images in response to voltage, temperature, and other factors has now been developed. The research team plans to prioritize its use in developing sensors that detect microorganisms or chemical substances.
The National Research Foundation of Korea announced that a research team led by Professor No Junseok of the Department of Mechanical Engineering and Professor Kim Younggi of the Department of Chemical Engineering at Pohang University of Science and Technology (POSTECH) developed an ultra-small hologram device that responds to external stimuli by combining metamaterials with liquid crystal technology. This research achievement was published on the 11th in the international journal Advanced Materials.
Holograms Responding to Voltage, Temperature, Finger Movements, and More
The research team integrated liquid crystals, which can easily change optical properties in response to external stimuli, with metamaterials. By combining a specially designed liquid crystal-based optical modulator on the metasurface, they developed a device that can respond to various external stimuli such as finger touch, voltage, or heat depending on the materials and design of the liquid crystal cell.
In the case where liquid crystals designed to respond to voltage were integrated, applying a voltage of 0.8 volts (V) or 1V can rapidly change the hologram image within a few milliseconds (ms, 0.001 seconds).
The device integrated with liquid crystals that respond to temperature changes the hologram image when the temperature exceeds 47°C. The device designed to respond to touch can quickly change the hologram image with a light finger touch ranging from 10 kilopascals (kPa) to 0.01 megapascals (MPa).
Notably, it was found that very clear hologram images can be generated in the visible light range with wavelengths between 450 and 700 nanometers (nm).
Integration into Sensors Detecting Microorganisms and Chemical Substances
The research team stated, "The developed ultra-small hologram device will be a clue to advancing high-definition holographic video playback optical devices, temperature-responsive hologram sensors, and future interactive and haptic hologram technologies," adding, "We plan to continue research to integrate this device into sensors that detect microorganisms or chemical substances."
Meanwhile, metamaterials are artificial materials that do not exist in nature. They are called dream materials capable of realizing new optical functions such as invisibility cloaks, super lenses, and acoustic refraction devices. Researchers in Korea and abroad are conducting studies to implement future displays such as 3D holographic displays and augmented, virtual, and mixed reality using metasurfaces?ultrathin, ultralight, and ultra-small optical devices about one-thousandth the thickness of a human hair. However, devices using existing metasurfaces could not change their optical properties once fabricated, so only a single pre-programmed image could be displayed in space.
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