Synthesis of the Thioborate Crystal Zn_xBa₂B₂S_5+x (x ≈ 0.2) for Second Order Nonlinear Optical Applications

Abstract

Thioborate materials have been considered for novel infrared nonlinear optical (NLO) materials having large optical nonlinear properties combined with favorable laser damage thresholds and wide transmission ranges from the visible to the mid-infrared regions. In this work, known and new thioborate materials have been investigated that have the potential to overcome the low laser damage thresholds of the NLO chalcopyrite sulfide materials such as AgGaS2 without losing their large nonlinear properties and wide transmission ranges. A new thioborate phase, polycrystalline ZnxBa2B2S5+x (x ≈ 0.2), has been prepared by the reaction of the metal sulfides and B2S3 glass in carbon crucibles sealed inside evacuated silica tubes. It crystallizes in the tetragonal system with unit cell parameters of a = 4.762(4) Å and c= 24.020(7) Å and is based on isolated (BS3)3-structural units. The second harmonic generation (SHG) efficiency determined on powders of ZnxBa2B2S5+x (x ≈ 0.2) is 50 times larger than that of α-SiO2. The infrared spectrum shows transparency from 2.5 to 10 μm with absorption bands around 12 μm related to the vibration modes of (BS3)3-units. The UV−visible spectrum shows that it is transparent in the visible region down to 350 nm, which is a large improvement over the absorption edge of AgGaS2 at 490 nm. ReceiVed September 27, 2004. ReVised Manuscript ReceiVed February 18, 2005 Thioborate materials have been considered for novel infrared nonlinear optical (NLO) materials having large optical nonlinear properties combined with favorable laser damage thresholds and wide transmission ranges from the visible to the mid-infrared regions. In this work, known and new thioborate materials have been investigated that have the potential to overcome the low laser damage thresholds of the NLO chalcopyrite sulfide materials such as AgGaS 2 without losing their large nonlinear properties and wide transmission ranges. A new thioborate phase, polycrystalline Zn x Ba 2 B 2 S 5+x (x ≈ 0.2), has been prepared by the reaction of the metal sulfides and B 2 S 3 glass in carbon crucibles sealed inside evacuated silica tubes. It crystallizes in the tetragonal system with unit cell parameters of a ) 4.762(4) Å and c ) 24.020(7) Å and is based on isolated (BS 3 ) 3-structural units. The second harmonic generation (SHG) efficiency determined on powders of Zn x Ba 2 B 2 S 5+x (x ≈ 0.2) is ∼50 times larger than that of R-SiO 2. The infrared spectrum shows transparency from 2.5 to 10 µm with absorption bands around 12 µm related to the vibration modes of (BS 3 ) 3-units. The UV-visible spectrum shows that it is transparent in the visible region down to ∼350 nm, which is a large improvement over the absorption edge of AgGaS 2 at 490 nm.

Synthesis, Structure, and Properties of Nonlinear Optical Crystal Na2SiF6

“…Nonlinear optical (NLO) materials have attracted extensive commercial and academic interest because of their applications in a broad range of fields, such as second harmonic generators (SHG), semiconductor photolithography, catalysis, molecular sieves, microelectronics, biomedicine, photonics, and material processing . After continuous efforts over several decades, various high‐performance NLO crystals have been obtained, such as, KBe 2 BO 3 F 2 (KBBF), β‐BaB 2 O 4 (β‐BBO), KH 2 PO 4 (KDP), KTiOPO 4 (KTP), AgGa Q 2 ( Q = S, Se), and ZnGeP 2 , which have been widely used as optoelectronic devices.…”

KEu2In3B12S13: a novel type of thioborate featuring B12S12 cluster and unique In6S6 12-membered ring

“…[26][27][28][29][30][31][32][33] The combination of borates and chalcogenides has also demonstrated promising NLO and special magnetic properties. [34][35][36] Therefore, it is interesting to combine these aspects to explore chalcogenoborates as new functional materials.…”

BaB2S4: An Efficient and Air-Stable Thioborate as Infrared Nonlinear Optical Material with High Laser Damage Threshold

“…Thioborates, just like borates, have a rich structural chemistry. The coordination numbers of the B atoms in thioborates can be either three (the [BS 3 ] 3– groups) or four (the [BS 4 ] 5– tetrahedra) forming 0D-cluster, 1D-chain, 2D-layer, and 3D-network. − Additionally, similar bond length between S–S (1.890 Å) and B–S (2.078 Å) in perthioborates can make the connection modes of the B–S units additional various structure types with unusual S–S bonds, including [B 2 S 5 ] 2– cluster, [BS 3 ] − chain, [B 3 S 10 ] 3– chain, and [B 2 S 7 ] 2– chain . Trigonal-planar [BS 3 ] 3– units can tend to form isolated clusters, including [BS 3 ] 3– , [B 2 S 4 ] 2– , [B 2 S 5 ] 2– , [B 3 S 6 ] 3– , etc., and tetrahedral [BS 4 ] 5– units are always connected to form T n -supertetrahedra cluster, , such as [B 4 S 10 ] 8– (T 2 ) and [B 10 S 20 ] 10– (T 3 ) .…”