The research team has created a new two-dimensional photonic time crystal that could improve laser and wireless communications

Recently, a team of researchers announced that they had developed a way to make photonic time crystals and demonstrated that such time-based artificial optical materials can amplify the light shining on them. Ultimately, these photonic crystals are expected to lead to more efficient and powerful wireless communications and significantly improved lasers.

The findings are described in a paper published today in the journal Science Advances. The findings come from researchers at Aalto University, the Karlsruhe Institute of Technology (KIT) and Stanford University.

(Photo credit: Aalto University)

Back in 2012, Nobel laureate Frank Wilczek first proposed the concept of time crystals: ordinary, familiar crystals have structural patterns that repeat in space, while in a time crystal this pattern can be repeated in time. Last year, researchers at Aalto University's Cryogenic Laboratory created pairs of time crystals that could be used in quantum devices.

Now, another team of researchers has developed photonic time crystals that operate at microwave frequencies and demonstrated that they can amplify electromagnetic waves -- an ability that has potential applications in a variety of technologies, including wireless communications, integrated circuits and lasers.

So far, research on photonic time crystals has focused on bulk materials (i.e., three-dimensional structures), which have proved challenging, and experiments have yet to develop a model system for practical applications.

The team that developed the new photonic time crystal tried a new approach: building a two-dimensional photonic time crystal, called a metasurface.

By "reducing the dimensions" of a three-dimensional structure to a two-dimensional one, they have made it easier to manufacture photonic time crystals under practical conditions. The team said they had been able to create photonic time crystals and experimentally verified theoretical predictions about their behaviour: "We have demonstrated for the first time that photonic time crystals can amplify incident light with high gain."

In a photonic time crystal, the photons are arranged in a pattern that repeats over time. This means that the photons in the crystal are synchronized and coherent, which can lead to interference and amplification of light. The periodic arrangement of photons means that they can also interact in a way that amplifies them.

Two-dimensional photonic time crystals have a wide range of applications:

First, by amplifying electromagnetic waves, they can make wireless transmitters and receivers more powerful or efficient. Coating the surface with two-dimensional photonic time crystals could also help with signal attenuation, an important problem in wireless transmission, the researchers note. Photonic time crystals can also simplify laser design by eliminating the large reflectors typically used in laser cavities.

In addition, two-dimensional photonic time crystals amplify not only the electromagnetic waves that hit them in free space, but also those that travel along the surface. Surface waves are used to communicate between electronic components in integrated circuits, and by integrating two-dimensional photonic time crystals into the system, surface waves can be amplified, thus improving the efficiency of communication.

Source: OFweek