The laser is one of the most versatile technologies in the scientific world, with applications in practically all fields of science. One of its most interesting qualities is that it concentrates a lot of energy in a very small space. But this requires, despite the redundancy, a lot of energy and this requires a large infrastructure. Reduce this is a key to the advancement of new laser devices, portable but equally powerful. And this is what researchers at Rensselaer Polytechnic Institute have achieved.
Scientists led by Wei Bao have manufactured a device no wider than a human hair which will help physicists investigate the fundamental nature of matter and light. The findings, published in Nature Nanotechnology, could also support the development of more efficient lasers.
The device is made of a special type of material called photonic topological insulator. This material can guide photons (the wavy particles that make up light) to specifically designed interfaces within the material while preventing these particles from scattering through the material itself.
Due to this property, topological insulators can make that many photons act coherently as a single photon, the key to a laser. 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 photonic topological insulator we created is unique – explains Bao -. It works at room temperature and this is an important advance. Previously, research could only be done using large, expensive equipment that cools matter in a vacuum. Many research laboratories do not have access to this type of equipment, so our device could allow more people to do this type of basic physics research. It is also a promising step forward in the development of lasers that require less energy to operate, since the threshold of our device at room temperature (the amount of energy needed for it to operate) is seven times lower than that of low temperature devices developed to date.
To create their device, the researchers grew ultrathin plates of perovskite halide, a crystal made of cesium, lead and chlorine, and etched a polymer on top with a pattern. They sandwiched these glass and polymer plates between sheets of various oxide materials, ultimately forming an object of approximately 2 microns thick and 100 microns long and wide (the average human hair is 100 microns wide).