Effect of rare-earth doping on the structural and optical properties of the Ag3AsS3 crystals

Abstract

Non-linear optical (NLO) materials allow the production of the coherent laser beam in the di cult frequency ranges of the electromagnetic spectrum. Aiming to explore new classes of the NLO materials with high optical performance in the infrared (IR) region, in this work, we investigated the effect of the rare earth doping (Pr, Eu, Yb) on the crystal structure and optical properties of the Ag 3 AsS 3 crystals. The performed analysis of the XRD patterns indicates that the rare earth elements are located in the Ag sites of the crystal lattice. As a result, the second harmonic generation (SHG) intensity, which determines the effectiveness of the NLO materials, increases with the increase of rare earth dopant content up to 1.0 %.Using the absorption analysis and Raman spectroscopy, we show that the increase in the SHG intensity can be related to the slight decrease of the bandgap, as well as with the increased electron-phonon interaction in rare-earth-doped Ag 3 AsS 3 crystals. Considering the discovered enhancement of the SHG intensity, accompanied by the low melting temperature, this work offers rare-earth-doped Ag 3 AsS 3 crystals as potential candidates for the non-linear optical applications for the infrared frequency range.

Homoatomic Polychalcogenide Nonlinear Optical Anionic Groups with Ultra-Large Optical Anisotropy

“…40,52 As an important inorganic system, chalcogenides show superiority for advanced NLO materials applied in the mid-infrared (mid-IR, 3−20 μm) region, mainly because of their excellent optical transparency, especially covering two practically important atmospheric windows (3−5 and 8−12 μm). 40,53−59 In addition, many chalcogenides exhibit suitable NLO effects and birefringence as mid-IR NLO materials, 57−59 which also contain five kinds of NLO motifs above, such as octahedral (TiS 6 ) 8− in TiP 2 S 6 , 60 tetrahedral (GaS 4 ) 5− /(GaSe 4 ) 5− in AgGaS 2 /AgGaSe 2 , 44,61 planar (B 3 S 6 ) 3− in LiBaB 3 S 6 , 62 conical (AsS 3 ) 3− in Ag 3 AsS 3 , 63 and chained (CNS) − in CuCNS. 64 In addition to the above five NLO motifs, in this study, we discover another kind of unique polychalcogenide anionic motif, i.e., the homoatomic anionic clusters formed by aggregated anions Q (= S, Se, Te), that can exhibit potential mid-IR NLO properties, including broad optical transparency, strong NLO effects, and ultra-large birefringence.…”

“…Till now, important acentric NLO motifs mainly include five categories: (I) octahedral motifs induced by Jahn–Teller distortion, e.g., (TiO 6 ) 8– in KTiOPO 4 , and (NbO 6 ) 7– in LiNbO 3 ; , (II) tetrahedral motifs induced by parallel polar alignment, e.g., (PO 4 ) 3– in KH 2 PO 4 , and (GaS 4 ) 5– in AgGaS 2 ; , (III) planar motifs induced by conjugated π-orbitals, e.g., (B 3 O 6 ) 3– in β-BaB 2 O 4 , and (BO 3 ) 3– in KBe 2 BO 3 F 2 ; , (IV) conical motifs induced by polar lone electron pairs, e.g., (BiO 4 ) 5– in α-BiB 3 O 6 , and (IO 3 ) − in LiIO 3 ; , and (V) chained motifs induced by dipole distortion, e.g., (CON 2 H 4 ) in urea, and (CN) − in CNI. , These basic NLO motifs and their composite groups are further combined to form a rich variety of NLO structures. ,,,,, Accordingly, the macro NLO performance of crystals can be achieved or controlled by proper alignment and assembly of the primitives. , As an important inorganic system, chalcogenides show superiority for advanced NLO materials applied in the mid-infrared (mid-IR, 3–20 μm) region, mainly because of their excellent optical transparency, especially covering two practically important atmospheric windows (3–5 and 8–12 μm). ,− In addition, many chalcogenides exhibit suitable NLO effects and birefringence as mid-IR NLO materials, − which also contain five kinds of NLO motifs above, such as octahedral (TiS 6 ) 8– in TiP 2 S 6 , tetrahedral (GaS 4 ) 5– /(GaSe 4 ) 5– in AgGaS 2 /AgGaSe 2 , , planar (B 3 S 6 ) 3– in LiBaB 3 S 6 , conical (AsS 3 ) 3– in Ag 3 AsS 3 , and chained (CNS) − in CuCNS …”