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Single Metalens Focuses All Colors of the Rainbow in One Point

Single Metalens Focuses All Colors of the Rainbow in One Point

Metalens could Revolutionize AR and VR Technology

Currently, the lenses in use today, whether it be in a camera or otherwise use a number of lenses in order to correct what is known as a chromatic aberration. Coming to chromatic aberration later on, this use of multiple lenses causes the instrument or gadget it is used in to be bulky and complex in design.  Recently all that is changed, with researches having created a single metalens that is capable of overcoming chromatic aberration thereby resulting in a more compact and simple designed device. Having created a metalens, opens up various possibilities too in the VR and AR world.

What is a Metalens?

Metalens is a flat surface with nanostructures that focus all colors in a visible spectrum including white light into a single point.

Previously metalenses could only be used to focus a limited range of colors and the only other option was curved lenses that needed to be used in numbers just to overcome chromatic aberration resulting in a very bulky product.

Using multiple layers of curved lenses was necessary because of chromatic aberration. Different color’s wavelengths travel at different speeds through different materials, for example a red wavelength passes through glass faster than what a blue wavelength would. These colors would then reach a point at different times causing a different foci. This difference in foci is called a chromatic aberration.

So currently, in order that this problem of chromatic aberration is solved, a number of curved lenses made of different thickness and materials have been used that is until metalenses.

Advantages of a Metalens over traditional lenses:

Metalenses are made from materials that are cost effective, they are easy to make and are thin compared to today’s traditional lenses.

How has a Metalens taken care of the problem of Chromatic Abberation?

The research team has used arrays of titanium dioxide nanofins to create a metalens which also eliminates the problem of chromatic aberration. Researchers have used units of paired titanium dioxide nanofins to control the speed of various wavelengths simultaneously.

Another advantage of using paired nanofins is that they also control the refractive index on the metalens which creates time delays of the wavelengths passing through the different fins. This process ensures that all colors reach at the same time and at the same place.

Major problems to overcome in making a Metalens:

Researchers had to ensure that all the colors of the spectrum was focused at a single point and that they reached this point at the same time from different points on the metalens.

By joining two nanofins into one element, researchers were able to bring all the colors of a spectrum to focus on one point and all come at the same time to that one focal point.

This breakthrough invention will greatly reduce the thickness and complexity in design when it comes to optical devices such as cameras. This also opens up the AR and VR world of tech.

Researchers are now planning on developing a bigger 1 cm diameter metalens.

Tags : Optics
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