New method enhances long-wave infrared crystal performance

A new research study has found a simpler way to create long-wave infrared birefringent crystals. These crystals are important for technologies like infrared imaging, lasers, and optical communication. High-quality versions of these crystals have been hard to produce due to challenges with their properties and growth. The research team, led by Professor Kong Fang from the Fujian Institute of Research on the Structure of Matter in China, has introduced an "oxygenation strategy." This method involves replacing the monovalent halide ion in the crystal structure with a divalent oxygen ion. This change activates certain electrons, enhancing the crystal's birefringence, or ability to bend light differently based on polarization. The scientists focused on three new structures within the rubidium, antimony, and chlorine system: Rb 13 Sb 8 Cl 37, Rb 3 Sb 2 OCl 7, and Rb 2 Sb 2 OCl 6. They found that by changing the ratio of chlorine to antimony, the crystal structure changed in a way that improved the birefringent properties. One of the new crystals, Rb 2 Sb 2 OCl 6, was grown to a size of 6×6×2 mm. It has excellent transmission capabilities in a wide range of infrared light, showing good performance between 0.4 and 13.5 micrometers. Its birefringence is significantly higher than that of one of the other new compounds, indicating it is a promising material for future applications. Overall, this research opens up new possibilities for creating high-performance birefringent crystals. It also deepens the understanding of how crystal structure affects their optical properties, paving the way for advancements in infrared technology.