Gravity plays a significant role in affecting the path of light, a phenomenon that was pivotal in testing and confirming Albert Einstein’s theory of general relativity. This effect is most pronounced when cosmic objects with substantial mass are concentrated in a relatively small space, giving rise to gravitational lenses. In such situations, space-time is so severely warped that it behaves like a magnifying glass. Over time, this principle has been repeatedly validated through various observations and experiments.
Recent research has taken an intriguing twist by investigating whether a crystal could mimic the influence of gravity. The answer has been found to be affirmative. Scientists have achieved this by creating what they refer to as “pseudogravity” in a photonic crystal. A photonic crystal is a unique material that enables the manipulation of light as it traverses through it. Typically, these crystals are crafted by combining two or more materials in a specific pattern, forming a lattice structure that functions as “traffic controllers” for the movement of light.
In the context of this study, the researchers employed a distorted photonic crystal made from silicon. By introducing distortion into the crystal’s lattice, they effectively simulated the gravitational pull of massive objects, such as black holes. “We set out to explore whether lattice distortion in photonic crystals can produce pseudogravity effects,” senior author Professor Kyoko Kitamura from Tohoku University’s Graduate School of Engineering, said in a statement. “Much like gravity bends the trajectory of objects, we came up with a means to bend light within certain materials.
“This simulation was put to the test using terahertz waves, which straddle the boundary between infrared and microwaves. Terahertz waves find applications in scientific research, medical imaging, and security scans (as they can penetrate fabrics and plastics), and are even considered a potential medium for high-speed communication, ongoing efforts are exploring this application.
The ability to control terahertz waves in this manner not only offers insights into gravitational physics, enabling the emulation of various gravitational phenomena but also holds promise for future telecommunications networks. The versatility of this research underscores its potential significance in various scientific and technological domains.
“Such in-plane beam steering within the terahertz range could be harnessed in 6G communication. Academically, the findings show that photonic crystals could harness gravitational effects, opening new pathways within the field of graviton physics,” said study author Associate Professor Masayuki Fujita from Osaka University.