Metal Thiophosphates with Good Mid-infrared Nonlinear Optical Performances: A First-Principles Prediction and Analysis

Abstract

The family of metal thiophosphates is an important but long-ignored compound system of the nonlinear optical (NLO) materials with desirable properties for the mid-infrared (mid-IR) coherent light generation. In the present work, the mid-IR NLO capabilities of metal thiophosphate crystals are systematically investigated based on their structure-property relationship. The linear and nonlinear optical properties of these crystals are predicted and analyzed using the first-principles calculations. In particular, several metal thiophosphate compounds are highlighted to exhibit good mid-IR NLO performances, as supported by the primary experimental results. These candidates would greatly promote the development of the mid-IR NLO functional materials.

Na2BaMQ4 (M=Ge, Sn; Q=S, Se): Infrared Nonlinear Optical Materials with Excellent Performances and that Undergo Structural Transformations

“…Na 2 BaSnSe 4 and Na 2 BaGeSe 4 are found to be nonphasematchable and their SHG maximum intensities are about 1.3 and 0.9 times that of AGSatthe particle size of 55-88 mm, respectively.I na ddition, the SHG effects of Na 2 BaSnS 4 and Na 2 BaGeS 4 are circa 0.5 and 0.3 times that of AGSwith type-I phase-matching,respectively.Given that the SHG coefficient of AGS(d powder % 11 pm V À1 )isabout 33 times of that of KDP (d powder % 0.33 pm V À1 ), [15] Angewandte d ij = 3.76 pm V À1 and Dn = 0.037 , which agree well with the experimental results (Table 1). In combination, it is clear that Na 2 BaSnS 4 and Na 2 BaGeS 4 exhibit properties suitable for IR NLO applications (with d ij values,l arge E g values,a nd suitable Dn)a nd which are comparable to those of outstanding IR NLO materials,s uch as LiGaS 2 and LiInS 2 , [24,25] that have been verified to output IR energy.…”

“…According to previous research, agood IR NLO material should demonstrate acritical balance between E g values (> 3.0 eV) and d ij values (> 10 KDP,that is,more than 10 times the value of KH 2 PO 4 (KDP)), however only some metal chalcogenides can satisfy the above conditions and most of those have alkaline/alkaline-earth cations and easily distorted MQ 4 ligands (M = Ga, In, Ge,Sn; Q= S, Se) in their structures. [15] Therefore,i nt his work, we have combined into crystal structures MQ 4 tetrahedra (M = Ge, Sn;Q = S, Se) with alkaline/alkaline-earth (Na and Ba) cations to afford four IR NLO materials Na 2 BaSnS 4 , Na 2 BaSnSe 4 ,N a 2 BaGeS 4 ,a nd Na 2 BaGeSe 4 .Asuitable balance of E g and d ij values for Na 2 BaSnS 4 (3.27 eV and circa 17 KDP) and Na 2 BaGeS 4 (3.7 eV and about 10 KDP) are reported. Remarkably,t hese compounds undergo extraordinary structural changes from tetragonal (Na 2 BaSnS 4 )t o trigonal systems (Na 2 BaSnSe 4 ,Na 2 BaGeS 4 ,Na 2 BaGeSe 4 ).…”

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

“…The commercial MIR NLO materials are, AgGaQ 2 (Q = S, Se) [7,8] and ZnGeP 2 , [9] but each of them unfortunately suffers drawbacks that limit its applications.I ng eneral, outstanding MIR NLO materials should satisfy the following conditions:1 )strong second harmonic generation (SHG) coefficient d ij ;2 )large laser induced damage threshold (LIDT);3 )wide optical transparency,w hich is able to run across two important atmospherict ransparent windows (3-5 and 8-12 mm);4 )good IR phase-matchinga bility and moderate optical birefringence (0.03 < Dn < 0.10);5 )high thermal and environmental stabilitya nd so on. [11,12] On the other hand, an increase of E g would always result in ad ecrease of d ij in the MIR NLO materials. On the one hand, in order to achieve condition (1), the SHG effect should be d ij > 0.3 AgGaS 2 (AGS) (preferably 0.6 AGS), whereas condition (2) strongly depends on the band gap (E g )i nm aterials and the E g should be > 3.0 eV (preferably > 3.5 eV).…”

“…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 .…”

Predicting Global Minimum in Complex Beryllium Borate System for Deep-ultraviolet Functional Optical Applications

“…This method requires a good descriptor that can rapidly characterize relative properties, through using this descriptor to search new materials in enormous data repositories. This method has been successfully used for mid-infrared NLO materials30 and scintillators3132.…”