Guo Shengping of Yangzhou University and his collaborators published research papers on infrared nonlinear optical crystal materials on angelw

The second-order nonlinear optical (NLO) crystal materials in infrared band have important applications in the field of optoelectronics The research on them is one of the most important, difficult and hot topics in the field of laser and nonlinear optics Compared with other NLO materials, there are few commercial NLO materials, mainly aggaq 2 (q = s, Se) and ZnGeP 2 with chalcopyrite structure, but their low LIDT or TPA results in their limited application Therefore, it is of great significance to explore new NLO materials with excellent comprehensive properties Because of its wide infrared window and large NLO coefficient, chalcogenides have been the main research objects of NLO materials in the infrared region for many years In the exploration of new NLO materials, the main trend is that the chemical composition of materials is more and more diverse, the structure of materials is more and more complex, and some alkali metals or alkaline earth metals with high cost or chemical activity are introduced as counterions In contrast, the study of sulfur system with simple chemical composition and structure and without high cost or active metal cations has been ignored for a long time Recently, the NLO performance of cubic gallium selenide was studied by Guo Shengping, an associate professor of Yangzhou University It was published in angel Chem Int ed (DOI: 10.1002 / anie 201902839) under the title of "large second harmonic generation (SHG) effect and high laser ‐ induced damage threshold (LIDT) observed coexisting in gallium selenide" Guo Shengping's team found that the gallium selenide not only has large NLO effect (2.3 times of AgGaS 2), high LIDT (16.7 times of AgGaS 2), wide infrared window (0.59-25 μ m), but also can achieve phase matching As we all know, because the birefringence of cubic materials is zero, it is theoretically impossible to achieve phase matching This "contradictory" result prompted them to repeatedly verify the experimental results, and more than ten tests showed that the results were reliable Therefore, there must be "problems" in the structure of "cubic phase" gallium selenide obtained by their synthesis method Unfortunately, the single crystal X-ray diffraction technology cannot distinguish In order to better explain this abnormal phenomenon, Guo Shengping's team, in cooperation with Deng Shuiquan (theoretical calculation and analysis) and Guo guocong (further experimental verification) of Fujian Institute of material structure, Chinese Academy of Sciences, and through unremitting efforts, found that the "cubic phase" of gallium selenide was in fact a variety of subcrystalline cells (C2221, The difference between the energy of the three structures and the XRD of the powder is very small, so it is easy to be ignored This finding is verified by the experimental results of electron diffraction High throughput simulation shows that the symmetry of this kind of gallium selenide is lower than that of cubic phase, and the order or inherent defects of GA3 + ions at low temperature are conducive to the stable existence of this structure This work not only provides a successful new infrared NLO material, but also provides a successful research idea and example for the study of NLO materials similar to abnormal phenomena Guo Shengping, associate professor of Yangzhou University and Cheng Xiyue, assistant researcher of Fujian Institute of material structure, Chinese Academy of sciences are the first authors of this paper Most of the experimental work of this paper was completed by sun zongdong, a master student Guo Shengping, associate professor, Deng Shuiquan and Guo guocong are the corresponding authors Since joining Yangzhou University, Guo Shengping, associate professor, has mainly carried out the research on the crystal and infrared NLO properties of new types and new systems of metal sulfur compounds, and has made some progress, forming a distinctive research system A series of infrared NLO materials containing S8 molecular ring have been developed, and their properties are excellent This study has opened up a wide field of vision for the exploration of NLO materials of adducts (angelw Chem Int ed 2018, 57, 11540, VIP, frontispiece; inorg Chem 2018, 57, 11282; inorg Chem 2019, 58, 4619) At the same time, the electrical and magnetic properties of some novel chalcogenide crystals (J am Chem SOC 2019, 141, 9533; inorg Chem 2018, 57, 5343; inorg Chem 2019, 58, 3574) were explored In addition, in combination with the leading edge of the discipline and the understanding of the field, he successively published four review papers on the crystal and NLO performance of metal chalcogenide compounds (coord Chem Rev 2017, 335, 44; coord Chem Rev 2017, 347, 23; coord Chem Rev 2018, 374, 464; coord Chem Rev 2018, 368, 115).