Scientists slowed down light 10,000 times during the experiment

Scientists slowed down light 10,000 times during the experiment

Scientists have already established that light can be slowed down under certain conditions, and a new study demonstrates a method that promises to be one of the most useful. Researchers from Guangxi University and the Chinese Academy of Sciences in China say their method could benefit the development of computing and optical communications.

In a vacuum, light moves at only one speed – 299,792 kilometers per second. However, if there are electromagnetic fields in its path – such as the fields surrounding matter – this speed will begin to decrease.

Most transparent materials slow down light, but not much. It is the change in its speed that leads to the refraction of light when passing from one medium to another. But to actually slow down light, special materials are needed, such as photonic crystals or even supercooled quantum gases.

“We believe that our work opens up a completely new direction for realizing ultra-strong interactions of light and matter in nanophotonic chips,” the researchers write in their published work.

The new method is based on so-called electromagnetically induced transparency (EIT), where, with the help of special laser techniques, electrons are manipulated inside a gas stored in a vacuum, turning it from opaque to transparent.

The researchers adopted some of the principles of EIT in controlling light and developed a new material to slow down light. This material is a kind of metasurface – a synthetic two-dimensional structure with properties unlike any of those existing in nature.

The metasurfaces created by the team were made of very thin layers of silicon, and turned out to be much better than existing options for storing and releasing energy (in this case, light).

According to the results obtained by the researchers, light can be slowed down more than 10,000 times in this system. At the same time, light losses are reduced by more than five times, compared to other similar methods.

Key to the new approach is the way the metasurface’s smallest building blocks, known as meta-atoms, are arranged. In this case, they are close enough to blend into each other, which in turn affects how light is processed when passing through it.

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