Advances in Deep Ultraviolet Nonlinear Optical Crystal Materials

in Here is your first Forum Tue Dec 13, 2016 9:23 pm
by Eyes123456 • 33 Posts

Nonlinear optical crystal is an indispensable part of solid-state lasers, widely used in laser technology, optical communication, optical data storage and optical signal processing and so on. The use of nonlinear optical properties of the crystal, can achieve a variety of laser frequency conversion, is opening up a new way to the fundamental laser pointer source. In order to explore the UV / deep UV nonlinear optical crystal materials, the alkali metal and alkaline earth borate systems are given priority in the design and synthesis. In recent years, phosphate materials have the advantages of short UV cut-off edge, which is one of the research systems for exploring UV / deep UV nonlinear optical crystal materials.

Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing The new research team of optoelectronic functional materials, Pan Shilie, has been working on new nonlinear optical crystals in recent years. The team in the early non-linear optical crystal materials on the basis of results in the phosphate system with the introduction of second-order Jiang Taylor effect of metal cations Pb and alkali metals, high temperature molten liquid method successfully obtained non-linear optical crystal material APb2 (PO3) 5 (A = K, Rb, Cs). The results of spectral experiments show that the compound KPb2 (PO3) 5 has the ultraviolet cut-off edge of 177 nm, which is the shortest UV-blocking compound among lead-containing nonlinear optical crystal materials. The frequency doubling experiment showed that the compound KPb2 (PO3) 5 had KDR of 0.5 times and the compound of RbPb2 (PO3) 5 was 0.3 times of that of KDP, and the phase green laser pointer matching could be achieved at 1064 nm. Compared with the known compound RbBa2 (PO3) 5, the birefringence of compound KPb2 (PO3) 5 increased significantly (the birefringence value was 0.03 at 589.3 nm).

In order to clarify that the nonlinear optical crystal KPb2 (PO3) 5 containing lead has such a short UV cut-off edge, the properties of the material are calculated theoretically by the first principles. The calculated results show that there is almost no hybridization of Pb-6p and O-2p orbitals at the top of the valence band in the band component of the compound. According to the stereochemical mechanism, the stereoselectivity of the Pb atom in the compound KPb2 (PO3) 5 is very weak, which is the cause of the blue shift of the UV cut-off edge of the compound. This work provides a new idea for the design of UV deep UV nonlinear optical crystal materials.




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