Na₂ZnGe₂S₆: A New Infrared Nonlinear Optical Material with Good Balance between Large Second-Harmonic Generation Response and High Laser Damage Threshold

Abstract

The development of frequency-conversion technology in the infrared region is in urgent need of new excellent infrared nonlinear optical (IR NLO) materials. How to achieve a good balance between laser damage threshold (LDT) and NLO coefficient (dij) for new IR NLO candidates is still a challenge. The combination of the highly electropositive alkali metal (Na) and Zn with d(10) electronic configuration into crystal structure affords one new IR NLO material, Na2ZnGe2S6. It exhibits excellent properties including a wide transparent region (0.38-22 μm), large band gap (3.25 eV), and especially a balance between a strong NLO coefficient (30-fold that of KDP) and a high LDT (6-fold that of AgGaS2), indicating a promising application in the IR region. Moreover, novel common-vertex-linked wavelike ∞[GeS3]n chains are interestingly discovered in Na2ZnGe2S6, which rarely exist in the reported thiogermanides containing alkali metals. In addition, calculated SHG density and dipole moment demonstrate that the large NLO response is mainly attributed to the cooperative effects of the [GeS4] and [ZnS4] units.

Coexistence of Strong Second Harmonic Generation Response and Wide Band Gap in AZn4Ga5S12 (A=K, Rb, Cs) with 3D Diamond‐like Frameworks

“…Examples include LiGaS 2 , [13] BaGa 2 SiS 6 , [14] Na 2 BaGeS 4 , [15] Li 2 Ga 2 GeS 6 , [16] Li 2 In 2 SiS 6 , [17] LiInS 2 , [18] BaGa 4 S 7 , [19] Li 2 In 2 GeS 6 , [17] LiZnPS 4 , [12] BaAl 4 Se 7 , [20] LiGaSe 2 , [13] Na 2 BaGeS 4 , [15] Li 2 CdSnS 4 , [21] Na 2 ZnGe 2 S 6 , [22] Na 2 CdGe 2 S 6 , [23] BaGa 2 GeS 6 , [14] Li 2 CdGeS 4 , [24] SnGa 4 S 7 , [25] PbGa 4 S 7 , [26] Li 2 MnGeS 4 , [27] Li 4 HgGe 2 S 7 , [28] and Zn 3 (PS 4 ) 2 . Examples include LiGaS 2 , [13] BaGa 2 SiS 6 , [14] Na 2 BaGeS 4 , [15] Li 2 Ga 2 GeS 6 , [16] Li 2 In 2 SiS 6 , [17] LiInS 2 , [18] BaGa 4 S 7 , [19] Li 2 In 2 GeS 6 , [17] LiZnPS 4 , [12] BaAl 4 Se 7 , [20] LiGaSe 2 , [13] Na 2 BaGeS 4 , [15] Li 2 CdSnS 4 , [21] Na 2 ZnGe 2 S 6 , [22] Na 2 CdGe 2 S 6 , [23] BaGa 2 GeS 6 , [14] Li 2 CdGeS 4 , [24] SnGa 4 S 7 , [25] PbGa 4 S 7 , [26] Li 2 MnGeS 4 , [27] Li 4 HgGe 2 S 7 , [28] and Zn 3 (PS 4 ) 2 .…”

“…Recently,anewt ype of 3D DLF frameworkm aterial with the formula AX II 4 X III 5 Q 12 [A = alkali metal (K, Rb andC s);X II = transition metal (Mn, Zn, and Cd);X III = group 13 metal (Ga and In);Q= chalcogenide (S, Se, and Te )] attracted our attention and as ystematici nvestigation of this system was carried out. [22] Therefore, we are eager to achieve ab etter balanceb etween the NLO performance and E g (> 3.0 eV) in such DLFs throught he introduction of Zn 2 + ions. Moreover,o ngoing investigations have revealed that introduction of the lighter transition metal elements (such as Zn) into the crystal structure not only keeps the relatively large d ij but also increases the E g ;t ypical examples include Zn 3 (PS 4 ) 2 , [12] LiZnPS 4 , [12] and Na 2 ZnGe 2 S 6 .…”

Growth, Properties, and Theoretical Analysis of M2LiVO4 (M = Rb, Cs) Crystals: Two Potential Mid-Infrared Nonlinear Optical Materials

“…Remarkably, the reported materials show a relatively large E g among the known Mid-IR NLO crystals with high LDT i . e ., Pb 17 O 8 Cl 18 19 (3.44 eV and 12.8 × AgGaS 2 ), RbIO 3 (4.0 eV and about 20 × AgGaS 2 ) 21 , Na 2 BaSnS 4 (3.27 eV and about 5 × AgGaS 2 ) 17 and Na 2 ZnGe 2 S 6 (3.25 eV and 6 × AgGaS 2 ) 28 , which implies that the reported materials may be promising for application in high-energy laser systems. For comparison, although borate materials, such as β -BaB 2 O 4 (BBO) 4 , LiB 3 O 5 (LBO) 5 , possess a high LDT, they also show low optical transmittance in the Mid-IR (3–5 μm) range due to intrinsic vibration absorptions.

Figure 4Linear and nonlinear optical properties of RLVO and CLVO.

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“…The transmittance spectrum measurement indicates that CLVO has a wide transmission window range from 0.33 to 6.0 μm, which covers an important atmospheric transparent domain (3–5 μm). Remarkably, the reported materials show relatively large E g values (3.8 eV for RLVO and 3.7 eV for CLVO) and high LDT (about 28 × AgGaS 2 for RLVO and CLVO) among the known Mid-IR NLO crystals 17, 19, 21, 28 . The SHG measurements indicate that RLVO and CLVO have strong SHG efficiency of about 4 and 5 times that of KDP, respectively.…”

Spin-polarized Second Harmonic Generation from the Antiferromagnetic CaCoSO Single Crystal

“…These GeO 2 Se 2 tetrahedrons and BaOSe 6 polyhedrons are responsible for the large NLO response. Li et al 16. reported that the combination of the highly electropositive alkali metal (Na) and Zn with a d 10 electronic configuration into a crystal structure affords one new IR NLO material, Na 2 ZnGe 2 S 6 , which exhibits excellent properties including a wide transparent region, a large band gap, and especially a balance between the strong NLO coefficient (30 × KDP) and high LDT (6 × AgGaS2), which indicate a promising application in the IR region.…”