Two Tellurium(IV)-Based Sulfates Exhibiting Strong Second Harmonic Generation and Moderate Birefringence as Promising Ultraviolet Nonlinear Optical Materials

Abstract

Two tellurium(IV)-based sulfate nonlinear optical (NLO) materials, Te 2 O 3 (SO 4 ) and Te(OH) 3 (SO 4 )•H 3 O, were successfully synthesized via the mild hydrothermal method. Te 2 O 3 SO 4 has a two-dimensional (2D) structure consisting of [Te 6 O 12 ] ∞ layers as well as [SO 4 ] groups. Te(OH) 3 (SO 4 )•H 3 O features a simple 0D structure made up of an isolated [TeO 3 ] pyramid and a [SO 4 ] tetrahedra. Both of them are phase-matching materials and show remarkable powder second harmonic generation (SHG) efficiencies about 6 and 3 times that of KH 2 PO 4 (KDP), respectively, for Te 2 O 3 SO 4 and Te(OH) 3 (SO 4 )•H 3 O. Especially for Te(OH) 3 (SO 4 )•H 3 O, in addition to a large SHG response, it possesses a short UV cutoff edge (∼233 nm) as well as moderate birefringence (0.052@546.1 nm). Furthermore, theoretical calculations confirmed that their strong SHG effects are due to the synergistic effect of the [TeO 3 ] pyramid and [SO 4 ] tetrahedra.

A2BeS2O8 (A = NH4, K, Rb, Cs) Deep Ultraviolet Nonlinear Optical Crystals

“…The XRD patterns have testified that the residual products were BeO for (NH 4 ) 2 BeS 2 O 8 , K 2 SO 4 , and BeO and unreacted K 2 BeS 2 O 8 for K 2 BeS 2 O 8 , Rb 2 SO 4 , and BeO and unreacted Rb 2 BeS 2 O 8 for Rb 2 BeS 2 O 8 , Cs 2 SO 4 , and BeO and unreacted Cs 2 BeS 2 O 8 for Cs 2 BeS 2 O 8 after melting the compounds at 800 °C, respectively. Owing to the rigid three-dimensional frameworks, the thermodynamic stabilities of the alkali beryllium sulfates were superior compared with other reported UV NLO sulfates such as NH 4 NaLi 2 (SO 4 ) 2 (243 °C), (NH 4 ) 2 Na 3 Li 9 (SO 4 ) 7 (319 °C), Li 8 NaRb 3 (SO 4 ) 6 ·2H 2 O (165 °C), RbSbSO 4 Cl 2 (240 °C), CsSbF 2 SO 4 (280 °C), A 2 Bi 2 (SO 4 ) 2 Cl 4 (A = NH 4 , K, Rb) (220–300 °C), and Te 2 O 3 SO 4 (510 °C) . To the best of our knowledge, A 2 BeS 2 O 8 (A = K, Rb, Cs) should have the highest thermodynamic stabilities among all the reported NLO sulfates.…”

Synthesis, Crystal Structure, and Nonlinear Optical Property of an Anhydrous Sulfate KTb(SO4)2

“…As another non-π-conjugated material, the study of sulfate as an NLO material has been long neglected. Until recent years, sulfates as a potential UV/Deep UV NLO materials have gradually drawn people’s attention, and thus some sulfate NLO materials have emerged successively, for instance, Li 8 NaRb 3 (SO 4 ) 6 ·2H 2 O, NH 4 NaLi 2 (SO 4 ) 2 , NaBi­(SO 4 ) 2 ·H 2 O, NaCe­(SO 4 ) 2 ·H 2 O, NaY­(SO 4 ) 2· H 2 O, Rb 3 In­(SO 4 ) 3 , K 2 Mn 3 (SO 4 ) 3 F 2 ·4H 2 O, Te 2 O 3 (SO 4 ), KBiCl 2 SO 4 , K 3 Bi 2 Cl 5 O 2 (SO 4 ) 2 , etc. Nevertheless, the examples of sulfate systems as NLO materials are still extremely rare.…”

Explorations of New SHG Materials in Mercury Iodate Sulfate System**

“…[4] For example, NH 4 NaLi 2 (SO 4 ) 2 and (NH 4 ) 2 Na 3 Li 9 (SO 4 ) 7 produce moderate SHG responses (1.1 and 0.5 × KDP) at 1064 nm, and both have band gaps larger than 6.2 eV. [5] Although the microscopic SHG coefficient of SO 4 2À is small, its combination with cations with strong polarizability can result in materials with significant SHG performances, [6] such as Hg 3 O 2 SO 4 (14 × KDP at 1064 nm), [7] CeF 2 (SO 4 ) (8 × KDP at 1064 nm), [8] Te 2 O 3 (SO 4 ) (6 × KDP at 1064 nm) [9] and Rb 2 Bi 2 (SO 4 ) 2 Cl 4 (5.3 × KDP at 1064 nm). [10] Iodates are a class of outstanding nonlinear optical (NLO) crystals that have attracted wide research attentions.…”