The first topological quantum simulator in the strong light-matter interaction regime to operate at room temperatures

Researchers at Rensselaer Polytechnic Institute have fabricated a device no wider than a human hair that will help physicists probe the fundamental nature of matter and light. Their findings, published in the journal Nanotechnology of natureit could also support the development of more efficient lasers, which are used in fields ranging from medicine to manufacturing.

The device is made of a special type of material called a topological photonic insulator. A topological photonic insulator can direct photons, the wave-like particles that make up light, to specially designed interfaces within the material, while also preventing these particles from scattering through the material itself.

Because of this property, topological insulators can make many photons act coherently as one photon. The devices can also be used as topological “quantum simulators,” miniature laboratories where researchers can study quantum phenomena, the physical laws that govern matter at very small scales.

“The topological photonic insulator we created is unique. It works at room temperature. This is a major advance. Previously, this regime could only be investigated using large and expensive devices that supercool matter in a vacuum. Many research labs don’t have access to this kind of equipment, so our device could allow more people to pursue this kind of basic physics research in the lab,” said Wei Bao, assistant professor in RPI’s Department of Materials Science and Engineering and senior author of study.

“It is also a promising step forward in the development of lasers that require less energy to operate, as our device’s room-temperature threshold for the amount of energy required to operate it is seven times lower than devices developed previously with a low temperature,” Bao added.

RPI researchers created their new device with the same technology used in the semiconductor industry to make microchips, which involves layering different types of materials, atom by atom, molecule by molecule, to create a desired structure with specific properties.

To create their device, the researchers grew ultra-thin slabs of halide perovskite, a crystal made of cesium, lead and chlorine, and etched a polymer on top of it with a pattern. They sandwiched these crystal and polymer plates between sheets of different oxide materials, eventually forming an object about 2 microns thick and 100 microns in length and width (the average human hair is 100 microns wide).

When the researchers shone a laser light on the device, a glowing triangular pattern appeared at the interfaces designed into the material. This pattern, dictated by the device design, is a result of the topological characteristics of the lasers.

“Being able to study quantum phenomena at room temperature is an exciting prospect. Professor Bao’s innovative work shows how materials engineering can help us answer some of science’s biggest questions,” said Shekhar Garde. , dean of the RPI School of Engineering.