Despite the fact that modern cameras, microscopes and other optical equipment has reached an unprecedented level of development in recent years, optical technology that is used in all these devices and equipment really has not changed much since its invention in the beginning of 1700-ies. Even in the most high-end products generally used technology lensing, developed in about 1730, the year.
The main function of lens is to bring light of different wavelengths into a single beam, which otherwise would focus in different parts of the future image. The use of lenses allows to solve the problem of chromatic aberration or purple halo, which occurs in the case of defocus because light waves have different lengths. And although the lens in this quite effective to be used in the manufacture of various materials make them are not always convenient and expensive. In addition, their production requires a very careful and precise polishing, and optical alignment.
Scientists from the School of engineering and applied Sciences (SEAS) at Harvard University developed the solution. They created the “metacharacter”. It is a single layer surface of nanopillars (pictured above), located at a distance less than one wavelength between them that gives them the ability to manipulate phase, amplitude, and polarization of light levels, offering a simpler, cheaper and more effective method of correcting chromatic aberration.
The image obtained using metacharacter (left) and without (right)
An additional plus of the technology is that it can be used together with conventional refractive optical components, which opens wide opportunities for its application.
“Imagine that the light is divided into packets, which move with different speed and reach the desired point at different times. Using nanopillars packages will reach the focal point simultaneously,” explains Wei ting Chen, researcher of the laboratory of applied physics of the SEAS and the author of a published article that describes the invention in the journal Nano Letters.
Developers metacharacter say that technology is “fundamentally different” from traditional adjustment methods, as is used here nanostructural engineering.
“This allows us to go beyond the material limitations of the lenses and get much better performance,” adds co — designer Alexander Joo.
According to scientists, the technology can be used in all types of commercial optical systems, ranging from simple lenses to the most advanced microscopes that can use up to 14 high quality lenses.
The developers also added that going to further increase the efficiency of metacharacter technology can be used in compact optical devices and other advanced technology.
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