Li₇Cd_4.5Ge₄Se₁₆ and Li_6.4Cd_4.8Sn₄Se₁₆: Strong Nonlinear Optical Response in Quaternary Diamond‐Like Selenide Networks

Abstract

Two new selenides with diamond-like structures, Li Cd Ge Se and Li Cd Sn Se , were synthesized by using a conventional high-temperature solid-state reaction method. They crystallize in the space group Pna2 (no. 33) of the orthorhombic system. Their three-dimensional frameworks consist of corner-sharing LiSe , CdSe , and MSe (M=Ge, Sn) tetrahedra. These two compounds exhibit strong powder second-harmonic generation responses that are about 1.2 and 2.5 times that of the benchmark AgGaS at a laser wavelength of λ=2.09 μm, and also demonstrate type I phase-matchable behavior. The optical bandgaps were determined to be 2.18 and 1.95 eV for Li Cd Ge Se and Li Cd Sn Se , respectively. Furthermore, these two materials exhibit congruent melting behavior at rather low temperatures of 985 and 1060 K, respectively, which makes bulk single crystal growth by using the Bridgman-Stockbarger method possible. Our study indicates that these two materials show advantages over the traditional IR NLO material CdSe and are promising for practical applications.

Mid-Infrared Nonlinear Optical Halides with Diamond-like Structures: A Theoretical and Experimental Study

“…, E g vs d ij ) as much as possible on the premise of suitable mid-IR transparency. Such performance balance was originally proposed by our group to screen metal halides and thiophosphates. , As a primary screening criterion, the balance has rapidly located the range of potential systems, yielding comprehensive developments in subsequent theoretical and experimental studies containing diverse [MX n ] and [MQ n ] (where M = metal cations; X = F, Cl, Br, I; Q = S, Se, Te) structural motifs. , Especially in chalcogenide systems, this “structure-guiding-discovery” concept has led to the construction of the family treemap of mid-IR NLO crystals with ideal and/or defective diamond-like structures, from which the development of a series of diamond-like NLO chalcogenide crystals has been directly promoted. − …”

Li4HgSn2Se7: The First Second-Order Nonlinear Optical-Active Selenide in the I4–II–IV2–VI7 Diamond-like Family

“…Moreover, its SHG response is about 3.6 times that of AgGaS 2 at the largest particle size. Some other quaternary DL metal chalcogenides have also been reported to exhibit an NLO response. ,, However, they just show a weak SHG response or exhibit non-phase-matchability, which may restrict their further applications. For example, β-Li 2 ZnGeS 4 exhibits SHG conversion efficiencies about 0.7 times that of AgGaS 2 .…”