Optical Crystals

Researchers Develop Unconventional Strategy to Create Nonlinear Optical Crystals


Scientists led by Prof. Guo Guocong from the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, have successfully developed two novel non-centrosymmetric chalcogenides using an unconventional cationic substitution strategy. These chalcogenides, known as M (M = A/Ba, A = K, Rb), exhibit excellent properties as nonlinear optical crystals. The study was published in Small on September 11.

Nonlinear optical (NLO) crystals used in infrared (IR) applications need to possess several key advantages, such as a wide transmittance range, a strong laser-induced damage threshold (LIDT), a sufficient birefringence index, and physicochemical stability. However, achieving both a strong NLO coefficient and a wide band gap for high LIDT in a single material is a challenging task.

Traditionally, diamond-like chalcogenides have been considered potential candidates for IR NLO materials. However, their narrow band gaps often result in limited LIDTs. In this study, the researchers employed an unconventional cationic substitution strategy to develop two novel salt-inclusion sulfides, M (M = A/Ba, A = K, Rb). By introducing mixed cations into the GaS4 anionic frameworks, the researchers were able to achieve wide band gaps (3.04 and 3.01 eV) and significantly improve the LIDTs (9.4 and 10.3 × AgGaS2@1.06 μm).

Additionally, the researchers found that the ordered arrangement of tetrahedral GaS4 units in the crystal structures favored strong second-harmonic generation intensities (0.84 and 0.78 × AgGaS2@2.9 μm).

This study showcases the effectiveness of employing a cationic substitution strategy based on diamond-like structures to create high-performance NLO materials. The use of unconventional approaches like this can pave the way for the development of advanced optical crystals with enhanced properties.

1. Source: Coherent Market Insights, Public sources, Desk research
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