NC State researchers have improved the techniques used to compress infrared light using thin films, potentially opening the door for more useful applications in advanced infrared imaging technologies. The work demonstrated that the tech can “squeeze” a wider range of wavelengths while propagating the light at least four times further than previously thought.
Building on previous research using a silicon substrate, the improvements made by the researchers resulted in exceptionally low loss, allowing the light to propagate further since little energy is lost to heat.
“From an efficiency standpoint, this thin film is comparable to the most efficient polaritonic materials, which means that these films will be useful for practical applications,” said Yin Liu, assistant professor of materials science and engineering at North Carolina State University.
While testing the films at the Advanced Light Source at the Lawrence Berkeley National Laboratory as part of their recent research, the team also discovered that the thin film could confine both far- and mid-infrared light.
“When we tested the strontium titanate on a silicon substrate, it could only squeeze mid-infrared light,” said Ruijuan Xu, assistant professor of materials science and engineering at NC State. “We knew that, theoretically, it could confine far-infrared light, but we now have the experimental evidence to prove it.”
“The ability to confine far-infrared light is important from a practical standpoint,” Liu added. “For example, it will be useful in engineering thermal management technologies to convert heat into infrared light. And being able to operate in a broader range of infrared wavelengths also expands the utility of these materials for developing molecular sensing technologies.”
“Our earlier work established a new class of optical materials for controlling light in infrared wavelengths, which has potential applications in photonics, sensors and thermal management,” said Xu. “Our new work provides a deeper understanding of these materials and their properties, improving our ability to engineer these materials and incorporate them into practical applications.”
“Another exciting aspect of these materials is that the technique we use to create these thin films is more scalable than the techniques used to create other polaritonic materials,” concluded Liu. “Again, this helps to pave the way for practical use.”