There are many different ways to generate a hologram, each with its own advantages and disadvantages. Trying to maximize the advantages, researchers in a new study have designed a hologram made of a metamaterial consisting of aluminum nanorods that can produce light across the entire visible spectrum, and do so in a way that yields brighter images than other methods.
The researchers, led by Din Ping Tsai at National Taiwan University and Academia Sinica, both in Taipei, Taiwan, have published a paper on the new hologram in a recent issue of Nano Letters.
As the researchers explain, multicolor holograms have existed for many years and are often used on credit cards and for other security purposes. These "rainbow holograms" mix red, blue, and green light under white light illumination to produce a variety of colors. The main drawback, however, is that a viewer sees different colors depending on the viewing angle, which has limited the applications of these holograms.
More recently, researchers have demonstrated that an alternative way to generate multicolor holograms involves metamaterials—man-made materials composed of repeating patterns of small structures, allowing their optical properties to be tuned. Holograms made of metamaterials are called "meta-holograms."
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