A group of Chinese researchers have invented a new energy-efficient, ultra-thin optical crystal using a novel theory that lays the foundation for next-generation laser technology.
The twisted boron nitride developed by the team has a thickness of micrometers, making it the world's thinnest known optical crystal, Professor Wang Enge of Peking University's School of Physics recently told Xinhua. Compared with conventional crystals of the same thickness, its energy efficiency has increased by 100 to 10,000 times.
Wang, an academician at the Chinese Academy of Sciences, said the results are an original innovation in China's theory of optical crystals and open up a new field of making optical crystals from light-element two-dimensional thin-film materials.
In the past 60 years, research and development of optical crystals have been guided mainly by two phase-matching theories proposed by American scientists.
However, due to the limitations of the traditional theoretical models and material systems, the existing crystals are difficult to meet the requirements of miniaturization, high integration, and functionalization of laser devices for future development. The development of next-generation laser technology requires breakthroughs in optical crystal theory and materials.
Wang Engo and Prof. Liu Kaihui, director of the Institute of Condensed Matter and Materials Physics, School of Physics, Peking University, led a team to develop a third phase matching theory based on light element material systems - the twisted phase matching theory.
"The thickness of TBN crystals ranges from 1 to 10 micrometers. Most of the optical crystals we knew before had thicknesses at the level of one millimeter or even centimeters," Liu added.
The TBN production technology is currently being patented in the U.S., U.K., Japan and other countries. The team has produced prototype TBN lasers and is working with companies to develop next-generation laser technology.
With its ultra-thin size, excellent integration potential, and new functions, TBN crystals are expected to realize new application breakthroughs in the future in fields such as quantum light sources, photonic chips, and artificial intelligence.
