Until very recently, the photonics industry focused primarily on how to transmit information, replacing electrical signals through cables with laser pulses in optical fibers. “Currently,” explains Professor Álvaro Gil González, one of the project coordinators, “the possibility of creating materials that allow us to control the flow of light has led to the idea of developing optical devices that can process information using only visible or infrared light, thus replacing electrons as transmitters and processors of information.”.
In this vein, photonic crystals represent a new type of material that makes it possible to control the flow of light at a microscopic scale. They are characterized by their ordered structure, resembling a crystalline structure, with nanometric dimensions, in which the propagation of light in all directions can be prohibited. As the researcher explains, "These are highly ordered materials, but if defects are introduced within them that disrupt the crystal's geometry, then light conduction becomes possible in those regions." Consequently, "light can be guided in a controlled manner through the material, more efficiently than in optical fibers," he asserts.
The workings of these crystals and their many applications are now well understood, but the difficulty lies in their fabrication and manipulation. “The key is being able to build these types of structures, since they require very specific materials with a high refractive index, and we also have to work at the nanoscale,” explains the researcher. In this regard, the USC team is delving deeper into developing methodologies that will allow these materials to be manufactured industrially.
Multiple Applications
These materials have very diverse applications. “One of their possibilities lies in the development of optical circuits, which would allow the creation of integrated devices for transmission, amplification… and even a true photonic chip,” explains Gil. Furthermore, they can be used to design fibers that block infrared radiation, for the manufacture of clothing with these characteristics, or as thermal insulators.
Another potential application of these crystals would be to guide light through photonic optical fiber, whose operation differs radically from conventional optical fiber, allowing light to be guided with turns of up to 60 degrees. In addition, certain devices based on photonic crystals can be used as chemical sensors or biosensors.
They could also replace electronic circuits in computers, be used to manufacture photonic transistors, or improve airport metal detectors and other security scanners. "And it would be possible to obtain lasers with higher efficiency than current ones," explains the researcher, who adds that "these crystals would increase the efficiency of conventional light bulbs by replacing their filament with a photonic crystal, thus preventing energy loss in the form of infrared radiation.".
In general, it involves processing and transmitting information using light, which would allow for a greater quantity and speed of information compared to that processed through conventional electronic circuits.
Three dimensions
The researchers are employing highly innovative techniques that require a high degree of precision. One such technique is "direct ink writing," which allows for the creation of three-dimensional structures. This technique involves using a computer-controlled device that precisely moves a syringe equipped with extremely small needles. This device injects "inks" in the form of a tubular structure 0.5 microns thick. Its movement in three dimensions makes it possible to construct three-dimensional structures composed of thin "tubes" of the injected material.
Source: USC
