New study reveals breakthrough in photonic time crystals

In a new study published in the journal Nanophotonics, scientists have discovered a new way to create photonic time crystals (PTCs) by modulating the refractive index at an unprecedented rate. This discovery could revolutionize the field of optics and lead to groundbreaking applications in the future.

Concept of photonic time crystals

Photonic time crystals are materials in which the refractive index increases and decreases rapidly over time. They are similar to the photonic crystals that cause phenomena such as rainbow glow in nature. However, PTCs are unique in that they exhibit temporal rather than spatial oscillations.

Until now, PTCs have only been observed in the lowest frequency part of the electromagnetic spectrum, particularly in radio waves. However, the new study demonstrates the possibility of creating stable PTCs in the near-visible part of the spectrum.


Lead author Mordechai Segev (Mordechai Segev) from the Technion – Israel Institute of Technology, as well as his co-authors Vladimir Shalaev and Alexandra Boltaseva from Purdue University conducted an experiment using very short pulses of laser radiation. These pulses were passed through transparent conducting oxide materials, causing a rapid shift in the refractive index.

The researchers used a probing laser beam to measure the refractive index changes. They observed that as the refractive index of the material returned to its normal value, the probe beam rapidly shifted to the red side and then to the blue side. These changes occurred within a single electromagnetic wave cycle, which is very important for PTC stability.

Unraveling the mystery

The most intriguing aspect of this study is the ultrafast relaxation of the refractive index. Normally, electrons excited to high energies in crystals take much longer to return to their ground state. The researchers admit that they do not yet fully understand how such fast relaxation occurs.

Implications and future applications

Shalaev, a co-author of the paper, believes that the ability to maintain PTC in the optical domain will open up new possibilities in the science of light. He compares this discovery to the early days of lasers, when physicists had a limited understanding of their potential applications.

Although the specific applications of PTCs are not yet known, scientists are excited about the possibilities. Potentially, these time crystals could revolutionize fields such as telecommunications, computing, and imaging. Further research is needed to fully unlock the potential of this revolutionary discovery.

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